fix(modal): prevent duplicate ModalManager declaration

window.ModalManager was set unconditionally, causing "Identifier
'ModalManager' has already been declared" when script tag in HTML
also loaded ModalManager before renderer.js required it.

Now checks !window.ModalManager before setting.

Amit Haridas

.github/workflows/ci.yml

@@ -0,0 +1,28 @@
+name: CI
+
+on:
+  push:
+    branches: [master]
+  pull_request:
+    branches: [master]
+
+jobs:
+  test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Run tests
+        run: npm test
+
+      - name: Run linter
+        run: npm run lint

.github/workflows/release.yml

@@ -0,0 +1,122 @@
+name: Release
+
+on:
+  push:
+    tags: ['v*']
+
+permissions:
+  contents: write
+
+jobs:
+  build-linux:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Download external tools (pandoc)
+        run: node scripts/download-tools.js
+
+      - name: Run tests
+        run: npm test
+
+      - name: Build Linux packages
+        run: npm run build:linux-ci -- --publish=never
+
+      - name: Upload Linux artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: linux-artifacts
+          path: |
+            dist/*.deb
+            dist/*.AppImage
+            dist/*.snap
+            dist/*.rpm
+          retention-days: 5
+
+  build-windows:
+    runs-on: windows-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Setup Node.js
+        uses: actions/setup-node@v4
+        with:
+          node-version: 20
+          cache: npm
+
+      - name: Install dependencies
+        run: npm ci
+
+      - name: Download external tools (pandoc)
+        run: node scripts/download-tools.js
+
+      - name: Run tests
+        run: npm test
+
+      - name: Decode certificate (if available)
+        if: ${{ env.CSC_LINK_BASE64 != '' }}
+        shell: pwsh
+        env:
+          CSC_LINK_BASE64: ${{ secrets.CSC_LINK_BASE64 }}
+        run: |
+          $bytes = [Convert]::FromBase64String("$env:CSC_LINK_BASE64")
+          [IO.File]::WriteAllBytes("${{ github.workspace }}\code-signing-cert.pfx", $bytes)
+          echo "CERT_AVAILABLE=true" >> $env:GITHUB_ENV
+
+      - name: Build Windows packages (signed)
+        if: ${{ env.CERT_AVAILABLE == 'true' }}
+        env:
+          CSC_LINK: code-signing-cert.pfx
+          CSC_KEY_PASSWORD: ${{ secrets.CSC_KEY_PASSWORD }}
+        run: npm run build:win-signed -- --publish=never
+
+      - name: Build Windows packages (unsigned)
+        if: ${{ env.CERT_AVAILABLE != 'true' }}
+        env:
+          CSC_IDENTITY_AUTO_DISCOVERY: 'false'
+        run: npm run build:win-unsigned -- --publish=never
+
+      - name: Upload Windows artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: windows-artifacts
+          path: |
+            dist/*.exe
+            dist/*.zip
+          retention-days: 5
+
+  release:
+    needs: [build-linux, build-windows]
+    if: always()
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Download Linux artifacts
+        uses: actions/download-artifact@v4
+        continue-on-error: true
+        with:
+          name: linux-artifacts
+          path: dist
+
+      - name: Download Windows artifacts
+        uses: actions/download-artifact@v4
+        continue-on-error: true
+        with:
+          name: windows-artifacts
+          path: dist
+
+      - name: Create GitHub Release
+        uses: softprops/action-gh-release@v2
+        with:
+          generate_release_notes: true
+          files: dist/*

.gitignore

@@ -8,14 +8,22 @@ Thumbs.db
 *.swp
 *.swo
 *~
-.vscode/
+.vscode/*
+!.vscode/launch.json
 .idea/
 *.iml
 out/
 .cache/
 .npm/
 .electron/
-package-lock.json
+# package-lock.json is intentionally tracked for reproducible CI builds
+
+# Downloaded tool binaries (fetched at build time via scripts/download-tools.js)
+bin/
+
+# Code signing certificates — never commit private keys
+*.pfx
+*.p12
 
 # Screenshots and temp files
 *.png.bak
@@ -33,4 +41,8 @@ pdf\ modal.png
 # Claude/AI development files
 .claude/
 CLAUDE.md
-agents.mdcoverage/
+agents.md
+coverage/
+
+# Superpowers brainstorm artifacts
+.superpowers/

.security-hardening/01-vulnerability-scan.md

@@ -0,0 +1,469 @@
+# Security Assessment Report: MarkdownConverter v4.0.0
+
+**Assessment Date:** 2026-03-15
+**Application:** MarkdownConverter - Electron-based Markdown editor and document converter
+**Target Version:** 4.0.0
+**Assessor:** Security Audit Agent
+
+---
+
+## Executive Summary
+
+This assessment identified **10 security findings** ranging from **Critical to Low severity**. The most significant concerns involve insecure Electron security configuration that could allow XSS attacks to escalate to full system access, arbitrary code execution via the REPL feature, and missing input validation on file operations.
+
+| Severity | Count |
+|----------|-------|
+| Critical | 2 |
+| High | 3 |
+| Medium | 3 |
+| Low | 2 |
+
+---
+
+## Vulnerability Findings
+
+### CVE-MC-001: Insecure Electron Security Configuration (Critical)
+
+**CVSS 3.1 Score: 9.6 (Critical)**
+**CWE-265: CWE-1021: Improper Restriction of Renderers**
+
+**Location:** `src/main.js` (lines 328-332)
+
+```javascript
+webPreferences: {
+  nodeIntegration: true,
+  contextIsolation: false,
+  spellcheck: true
+},
+```
+
+**Description:**
+The main application window has `nodeIntegration: true` and `contextIsolation: false`, which is the most insecure Electron configuration. This allows the renderer process direct access to Node.js APIs, meaning any XSS vulnerability in the markdown rendering or external content could lead to full system compromise.
+
+**Exploitability:**
+- An attacker who can inject malicious JavaScript (via markdown files, XSS in preview, or compromised dependencies) gains immediate access to:
+  - Full file system read/write via `fs` module
+  - Command execution via `child_process`
+  - Network access via `net` module
+  - All system resources
+
+**Attack Scenario:**
+1. User opens a malicious markdown file containing embedded JavaScript
+2. The JavaScript executes in the renderer with full Node.js access
+3. Attacker can read sensitive files, execute commands, exfiltrate data
+
+**Remediation:**
+```javascript
+webPreferences: {
+  nodeIntegration: false,
+  contextIsolation: true,
+  sandbox: true,
+  preload: path.join(__dirname, 'preload.js')
+}
+```
+
+**Note:** The preload.js file already implements a secure IPC bridge but it is not being utilized for the main window.
+
+---
+
+### CVE-MC-002: Arbitrary Code Execution via REPL Feature (Critical)
+
+**CVSS 3.1 Score: 9.3 (Critical)**
+**CWE-94: Improper Control of Generation of Code ('Code Injection')**
+
+**Location:** `src/main.js` (lines 4369-4396)
+
+**Description:**
+The `execute-code` IPC handler allows execution of arbitrary Python and Bash scripts through the REPL panel. While JavaScript execution appears to have been removed or limited, Python and Bash commands are executed via `execFile` with user-supplied code.
+
+**Vulnerable Code Pattern:**
+```javascript
+ipcMain.handle('execute-code', async (event, { code, language }) => {
+  // ...
+  if (language === 'python' || language === 'py') {
+    cmd = 'python';
+    args = ['-c', code];
+  }
+  // ...
+  execFile(cmd, args, { timeout }, (err, stdout, stderr) => {
+    // ...
+  });
+});
+```
+
+**Exploitability:**
+- Users can be tricked into running malicious code blocks
+- Markdown files can contain executable code blocks with "Run" buttons
+- No sandboxing or permission restrictions on executed code
+
+**Attack Scenario:**
+1. Attacker creates markdown file with malicious Python code block
+2. User clicks "Run" button in preview
+3. Python code executes with user's full permissions
+4. Attacker gains code execution on victim's machine
+
+**Remediation:**
+- Remove arbitrary code execution feature entirely, OR
+- Implement strict sandboxing (Docker, VM, or restricted Python environment)
+- Add user confirmation dialogs with clear warnings
+- Execute in isolated environment with no filesystem/network access
+- Implement allowlist of safe operations
+
+---
+
+### CVE-MC-003: Potential XSS in Markdown Rendering (High)
+
+**CVSS 3.1 Score: 8.0 (High)**
+**CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')**
+
+**Location:** `src/renderer.js` (lines 387-419)
+
+**Description:**
+While DOMPurify is used to sanitize HTML, several extensions to marked.js may bypass sanitization:
+
+1. **Custom Admonition Extension (lines 51-77):**
+```javascript
+marked.use({
+    extensions: [{
+        name: 'admonition',
+        // ...
+        renderer(token) {
+            const inner = this.parser.parse(token.text);
+            return `<div class="admonition admonition-${token.admonitionType}">
+                <div class="admonition-title">${icon} ${token.admonitionType...}</div>
+                <div class="admonition-content">${inner}</div>
+            </div>`;
+        }
+    }]
+});
+```
+
+2. **innerHTML Assignments (line 419):**
+```javascript
+preview.innerHTML = sanitizedHtml;
+```
+
+**Exploitability:**
+- Combined with CVE-MC-001, XSS leads to full system compromise
+- Custom markdown extensions may not be properly sanitized
+- Admonition type is directly interpolated into HTML without escaping
+
+**Remediation:**
+- Ensure all custom markdown extensions escape user input
+- Add Content Security Policy that blocks inline scripts
+- Use `textContent` instead of `innerHTML` where possible
+- Audit all custom marked.js extensions for XSS vectors
+
+---
+
+### CVE-MC-004: Missing Path Traversal Protection (High)
+
+**CVSS 3.1 Score: 7.8 (High)**
+**CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')**
+
+**Location:** `src/main.js` (lines 4241-4281)
+
+**Description:**
+The `list-directory` and `open-file-path` IPC handlers accept arbitrary file paths without validation:
+
+```javascript
+ipcMain.handle('list-directory', async (event, dirPath) => {
+  try {
+    if (!dirPath) { /* dialog */ }
+    // No path validation - accepts any path
+    const entries = fs.readdirSync(dirPath, { withFileTypes: true });
+    // ...
+  }
+});
+
+ipcMain.on('open-file-path', (event, filePath) => {
+  // No path validation
+  if (!fs.existsSync(filePath)) return;
+  const content = fs.readFileSync(filePath, 'utf-8');
+  mainWindow.webContents.send('file-opened', { path: filePath, content });
+});
+```
+
+**Exploitability:**
+- Malicious renderer code can read any file on the system
+- No restriction to a sandbox directory
+- Combined with XSS, attacker can exfiltrate sensitive files
+
+**Remediation:**
+```javascript
+const ALLOWED_DIRECTORIES = [app.getPath('documents'), app.getPath('desktop')];
+
+function isPathAllowed(filePath) {
+  const resolved = path.resolve(filePath);
+  return ALLOWED_DIRECTORIES.some(dir => resolved.startsWith(dir));
+}
+```
+
+---
+
+### CVE-MC-005: Weak Content Security Policy (High)
+
+**CVSS 3.1 Score: 7.5 (High)**
+**CWE-1021: Improper Restriction of Renderers**
+
+**Location:** `src/index.html` (line 5)
+
+```html
+<meta http-equiv="Content-Security-Policy" content="default-src 'self';
+  script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net;
+  style-src 'self' 'unsafe-inline' https://cdnjs.cloudflare.com;
+  img-src 'self' data: blob: file:;
+  font-src 'self' data:;
+  connect-src 'self' https://www.plantuml.com;">
+```
+
+**Description:**
+The CSP contains several security weaknesses:
+
+1. **`'unsafe-inline'` in script-src** - Allows inline script injection
+2. **`'unsafe-eval'` in script-src** - Allows `eval()` and similar functions
+3. **`https://cdn.jsdelivr.net`** - Allows scripts from external CDN (supply chain risk)
+4. **`file:` in img-src** - Allows loading local files as images (potential information disclosure)
+
+**Exploitability:**
+- XSS attacks can execute arbitrary scripts
+- External CDN compromise could inject malicious code
+- `eval()` enables dynamic code execution
+
+**Remediation:**
+- Remove `'unsafe-inline'` and `'unsafe-eval'`
+- Use nonces or hashes for inline scripts
+- Remove external CDNs or use Subresource Integrity (SRI)
+- Remove `file:` from img-src
+
+---
+
+### CVE-MC-006: Insecure Window Configuration for PDF Export (Medium)
+
+**CVSS 3.1 Score: 6.5 (Medium)**
+**CWE-1021: Improper Restriction of Renderers**
+
+**Location:** `src/main.js` (lines 2579-2585)
+
+```javascript
+const pdfWindow = new BrowserWindow({
+  show: false,
+  webPreferences: {
+    nodeIntegration: true,
+    contextIsolation: false
+  }
+});
+```
+
+**Description:**
+Hidden windows created for PDF export also have insecure configurations, allowing potential privilege escalation.
+
+**Remediation:**
+```javascript
+webPreferences: {
+  nodeIntegration: false,
+  contextIsolation: true,
+  sandbox: true
+}
+```
+
+---
+
+### CVE-MC-007: PlantUML Server Data Exfiltration (Medium)
+
+**CVSS 3.1 Score: 5.3 (Medium)**
+**CWE-359: Exposure of Private Information**
+
+**Location:** `src/renderer.js` (lines 470-487)
+
+```javascript
+const plantumlBlocks = preview.querySelectorAll('pre code.language-plantuml');
+plantumlBlocks.forEach((block) => {
+    const code = block.textContent;
+    // ...
+    const encoded = plantumlEncode(code);
+    const img = document.createElement('img');
+    img.src = `https://www.plantuml.com/plantuml/svg/${encoded}`;
+    // ...
+});
+```
+
+**Description:**
+PlantUML diagram content is sent to an external server (plantuml.com) for rendering. This could leak sensitive information contained in diagrams.
+
+**Exploitability:**
+- Diagrams containing proprietary information, system architecture, or internal processes are sent to third-party servers
+- No user consent or notification before external data transmission
+
+**Remediation:**
+- Use local PlantUML rendering with Java
+- Add user warning before sending data to external service
+- Implement opt-in for external rendering
+
+---
+
+### CVE-MC-008: Inconsistent Security Settings Across Windows (Medium)
+
+**CVSS 3.1 Score: 5.5 (Medium)**
+**CWE-1021: Improper Restriction of Renderers**
+
+**Description:**
+Security settings are inconsistent across different windows:
+
+| Window | nodeIntegration | contextIsolation | Security |
+|--------|-----------------|------------------|----------|
+| Main Window | true | false | Insecure |
+| About Dialog | false | true | Secure |
+| Dependencies Dialog | false | true | Secure |
+| ASCII Generator | false | true | Secure |
+| Table Generator | false | true | Secure |
+| PDF Export Window | true | false | Insecure |
+| Hidden Conversion Window | true | false | Insecure |
+
+**Remediation:**
+Apply secure configuration (`nodeIntegration: false`, `contextIsolation: true`) consistently across all windows.
+
+---
+
+### CVE-MC-009: Command Execution via External Tools (Low)
+
+**CVSS 3.1 Score: 4.4 (Low)**
+**CWE-78: Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')**
+
+**Location:** `src/main.js` (lines 1915-1972)
+
+**Description:**
+While the application uses `execFile` instead of `exec` (good practice), external tools (Pandoc, LibreOffice, FFmpeg, ImageMagick) are invoked with file paths that could potentially be manipulated.
+
+**Positive Finding:**
+The code correctly uses `execFile` with argument arrays instead of shell commands, mitigating most command injection vectors.
+
+**Remaining Risk:**
+- File paths are not validated against malicious names
+- Special characters in filenames could cause issues with external tools
+
+**Remediation:**
+- Validate file paths before passing to external tools
+- Sanitize filenames of special characters
+
+---
+
+### CVE-MC-010: Missing Dependency Version Pinning (Low)
+
+**CVSS 3.1 Score: 3.5 (Low)**
+**CWE-1035: Using Components with Known Vulnerabilities**
+
+**Location:** `package.json`
+
+**Description:**
+Dependencies use `^` version ranges which could allow automatic updates to versions with vulnerabilities:
+
+```json
+"dependencies": {
+  "marked": "^17.0.3",
+  "dompurify": "^3.3.1",
+  "mermaid": "^11.12.3",
+  // ...
+}
+```
+
+**Remediation:**
+- Pin exact versions in production
+- Use lockfile (package-lock.json)
+- Implement dependency scanning in CI/CD pipeline
+
+---
+
+## Attack Surface Map
+
+```
+┌─────────────────────────────────────────────────────────────────┐
+│                    EXTERNAL ATTACK SURFACE                       │
+├─────────────────────────────────────────────────────────────────┤
+│  Markdown Files (.md)     ─────► XSS via Preview Rendering      │
+│  Code Blocks              ─────► Arbitrary Code Execution       │
+│  PlantUML Diagrams        ─────► Data Exfiltration              │
+│  External CDNs            ─────► Supply Chain Attacks           │
+└─────────────────────────────────────────────────────────────────┘
+                              │
+                              ▼
+┌─────────────────────────────────────────────────────────────────┐
+│                    RENDERER PROCESS (Insecure)                   │
+├─────────────────────────────────────────────────────────────────┤
+│  nodeIntegration: true   ─────► Direct Node.js Access           │
+│  contextIsolation: false ─────► Prototype Pollution Risk        │
+│  DOMPurify Sanitization  ─────► May be bypassed via extensions  │
+│  Custom Marked Extensions ────► XSS Vectors                     │
+└─────────────────────────────────────────────────────────────────┘
+                              │
+                              ▼
+┌─────────────────────────────────────────────────────────────────┐
+│                    IPC BRIDGE (Preload.js)                       │
+├─────────────────────────────────────────────────────────────────┤
+│  Channel Whitelisting    ─────► Good Practice                   │
+│  Not Used for Main Window ────► Security Bypassed               │
+└─────────────────────────────────────────────────────────────────┘
+                              │
+                              ▼
+┌─────────────────────────────────────────────────────────────────┐
+│                    MAIN PROCESS (Full Privileges)                │
+├─────────────────────────────────────────────────────────────────┤
+│  File Operations         ─────► No Path Validation              │
+│  Code Execution          ─────► Python/Bash via REPL            │
+│  External Tools          ─────► Pandoc, FFmpeg, LibreOffice     │
+│  PDF Operations          ─────► Merge, Encrypt, Decrypt         │
+└─────────────────────────────────────────────────────────────────┘
+```
+
+---
+
+## Positive Security Findings
+
+1. **Preload.js Implementation:** A secure IPC bridge with channel whitelisting is implemented
+2. **DOMPurify Usage:** HTML sanitization is applied to markdown output
+3. **execFile Usage:** External commands use `execFile` instead of `exec`
+4. **File Size Limits:** 50MB maximum file size is enforced
+5. **Rate Limiting:** Conversion operations have rate limiting (2 second minimum interval)
+6. **Error Message Sanitization:** Absolute paths are stripped from error messages
+
+---
+
+## Prioritized Remediation Roadmap
+
+### Phase 1 - Critical (Immediate)
+1. Set `nodeIntegration: false` and `contextIsolation: true` for main window
+2. Remove or sandbox the code execution (REPL) feature
+3. Implement proper preload.js usage for all windows
+
+### Phase 2 - High Priority (1-2 Weeks)
+4. Add path traversal protection to file operations
+5. Strengthen Content Security Policy
+6. Audit and fix custom markdown extensions for XSS
+
+### Phase 3 - Medium Priority (1 Month)
+7. Implement consistent security settings across all windows
+8. Add local PlantUML rendering option
+9. Implement dependency scanning in CI/CD
+
+### Phase 4 - Low Priority (Ongoing)
+10. Pin dependency versions
+11. Add security headers to all generated HTML
+12. Implement security logging and monitoring
+
+---
+
+## Compliance Considerations
+
+- **OWASP Top 10 2021:** A03:2021 - Injection, A05:2021 - Security Misconfiguration
+- **OWASP ASVS:** V12 - File Handling, V13 - API Security
+- **NIST CSF:** PR.AC - Access Control, PR.DS - Data Security
+
+---
+
+## Conclusion
+
+The MarkdownConverter application has significant security vulnerabilities that could allow an attacker to execute arbitrary code, access sensitive files, and compromise the user's system. The most critical issue is the insecure Electron configuration combined with XSS attack vectors in the markdown rendering pipeline.
+
+**Overall Security Rating: HIGH RISK**
+
+The positive finding is that much of the security infrastructure (preload.js, DOMPurify) is already in place but not properly utilized. With focused remediation effort, the application can achieve a much stronger security posture.

.security-hardening/02-threat-model.md

@@ -0,0 +1,215 @@
+# STRIDE Threat Model - MarkdownConverter v4.0.0
+
+**Analysis Date:** 2026-03-15
+**Methodology:** STRIDE + MITRE ATT&CK
+**Overall Risk Score:** 7.8 (HIGH)
+
+---
+
+## Executive Summary
+
+The analysis identified **10 vulnerabilities** with a combined risk score of **7.8 (HIGH)**. The most critical issues enable complete system compromise through XSS-to-RCE attack chains.
+
+---
+
+## Critical Findings
+
+| Priority | CVE | Vulnerability | CVSS | Impact |
+|----------|-----|---------------|------|--------|
+| P0 | CVE-MC-001 | Insecure Electron Config (`nodeIntegration: true`, `contextIsolation: false`) | 9.6 | Complete system compromise |
+| P0 | CVE-MC-002 | Arbitrary code execution via REPL feature | 9.3 | Remote code execution |
+| P1 | CVE-MC-003 | XSS in markdown rendering | 8.0 | Session hijacking, RCE chain |
+| P1 | CVE-MC-004 | Path traversal vulnerability | 7.8 | Arbitrary file write |
+| P1 | CVE-MC-005 | Weak Content Security Policy | 7.5 | XSS enablement |
+| P2 | CVE-MC-006 | Insecure window config for PDF export | 6.5 | Privilege escalation |
+| P2 | CVE-MC-007 | PlantUML server data exfiltration | 5.3 | Information disclosure |
+| P2 | CVE-MC-008 | Inconsistent security settings | 5.5 | Configuration weakness |
+| P3 | CVE-MC-009 | Command execution via external tools | 4.4 | Command injection risk |
+| P3 | CVE-MC-010 | Missing dependency version pinning | 3.5 | Supply chain risk |
+
+---
+
+## Key Attack Vectors
+
+### 1. XSS to RCE Chain (Critical)
+```
+Malicious Markdown File
+        │
+        ▼
+XSS in Preview (CVE-MC-003)
+        │
+        ▼
+nodeIntegration: true (CVE-MC-001)
+        │
+        ▼
+Full Node.js Access
+        │
+        ▼
+Complete System Compromise
+```
+
+### 2. REPL Code Execution (Critical)
+```
+Code Block in Markdown
+        │
+        ▼
+User clicks "Run"
+        │
+        ▼
+REPL executes Python/Bash (CVE-MC-002)
+        │
+        ▼
+Arbitrary Code Execution
+```
+
+### 3. Data Exfiltration (Medium)
+```
+PlantUML Diagram Content
+        │
+        ▼
+Sent to www.plantuml.com (CVE-MC-007)
+        │
+        ▼
+Sensitive Architecture Leaked
+```
+
+---
+
+## STRIDE Analysis
+
+### S - Spoofing
+| ID | Threat | Likelihood | Impact | Risk |
+|----|--------|------------|--------|------|
+| S1 | Attacker spoofs markdown file origin | Medium | High | High |
+| S2 | Malicious code pretends to be safe | High | Critical | Critical |
+
+### T - Tampering
+| ID | Threat | Likelihood | Impact | Risk |
+|----|--------|------------|--------|------|
+| T1 | XSS modifies local files | High | Critical | Critical |
+| T2 | Conversion output tampered | Medium | Medium | Medium |
+
+### R - Repudiation
+| ID | Threat | Likelihood | Impact | Risk |
+|----|--------|------------|--------|------|
+| R1 | No audit trail for operations | Low | Low | Low |
+
+### I - Information Disclosure
+| ID | Threat | Likelihood | Impact | Risk |
+|----|--------|------------|--------|------|
+| I1 | XSS exposes file system | High | Critical | Critical |
+| I2 | PlantUML content leaked | Medium | Medium | Medium |
+| I3 | Error messages reveal paths | Low | Low | Low |
+
+### D - Denial of Service
+| ID | Threat | Likelihood | Impact | Risk |
+|----|--------|------------|--------|------|
+| D1 | Malicious code crashes app | Medium | Medium | Medium |
+| D2 | Large file exhausts resources | Low | Low | Low |
+
+### E - Elevation of Privilege
+| ID | Threat | Likelihood | Impact | Risk |
+|----|--------|------------|--------|------|
+| E1 | XSS → nodeIntegration → System | High | Critical | Critical |
+| E2 | REPL code execution | High | Critical | Critical |
+
+---
+
+## MITRE ATT&CK Mapping
+
+| Technique | ID | Applicability |
+|-----------|-----|---------------|
+| User Execution | T1204.002 | Malicious markdown file |
+| Command and Scripting Interpreter | T1059.007 | JavaScript via nodeIntegration |
+| Command and Scripting Interpreter | T1059.006 | Python via REPL |
+| Command and Scripting Interpreter | T1059.004 | Bash via REPL |
+| Exploit Public-Facing Application | T1190 | XSS in preview |
+| Data Exfiltration Over Web Service | T1043 | PlantUML server |
+| File and Directory Discovery | T1083 | Path traversal |
+
+---
+
+## Trust Boundaries
+
+```
+┌─────────────────────────────────────────────────────────────────────┐
+│                         TRUST BOUNDARY MAP                          │
+├─────────────────────────────────────────────────────────────────────┤
+│                                                                     │
+│   ┌─────────────┐         ┌─────────────────────────────────────┐  │
+│   │   USER      │ ──────► │        APPLICATION                  │  │
+│   │ (Untrusted) │         │  ┌───────────┐  ┌───────────────┐  │  │
+│   └─────────────┘         │  │ Renderer  │  │ Main Process  │  │  │
+│                           │  │ (Sandbox) │  │ (Privileged)  │  │  │
+│                           │  └─────┬─────┘  └───────┬───────┘  │  │
+│                           │        │  IPC           │           │  │
+│                           │        ▼                ▼           │  │
+│                           │  ┌─────────────────────────────┐   │  │
+│                           │  │      File System            │   │  │
+│                           │  └─────────────────────────────┘   │  │
+│                           └─────────────────────────────────────┘  │
+│                                           │                        │
+│                                           ▼                        │
+│   ┌─────────────────────────────────────────────────────────────┐ │
+│   │                    EXTERNAL SERVICES                         │ │
+│   │  • PlantUML Server (www.plantuml.com)                       │ │
+│   │  • CDN (cdn.jsdelivr.net, cdnjs.cloudflare.com) [REMOVED]   │ │
+│   │  • External Tools (Pandoc, FFmpeg, LibreOffice)             │ │
+│   └─────────────────────────────────────────────────────────────┘ │
+│                                                                     │
+└─────────────────────────────────────────────────────────────────────┘
+```
+
+---
+
+## Business Impact Analysis
+
+### Successful Attack Consequences
+
+| Impact Category | Estimate |
+|-----------------|----------|
+| Data breach costs | $500,000 - $5,000,000+ |
+| Regulatory fines (GDPR) | Up to 4% annual revenue |
+| Reputation damage | Incalculable |
+| Business disruption | Hours to days |
+
+### Affected Assets
+- User documents and files
+- System credentials
+- Proprietary information in diagrams
+- Application integrity
+
+---
+
+## Remediation Priority
+
+### P0 - Immediate (24-48 hours)
+1. **CVE-MC-001**: Set `nodeIntegration: false`, `contextIsolation: true`
+2. **CVE-MC-002**: Remove or sandbox REPL code execution
+
+### P1 - Short-term (1-2 weeks)
+3. **CVE-MC-003**: Audit markdown extensions for XSS
+4. **CVE-MC-004**: Add path validation (✅ COMPLETED)
+5. **CVE-MC-005**: Strengthen CSP (✅ COMPLETED)
+
+### P2 - Medium-term (1 month)
+6. **CVE-MC-006**: Consistent window security settings
+7. **CVE-MC-007**: Add local PlantUML option or warning
+8. **CVE-MC-008**: Audit all BrowserWindow configurations
+
+### P3 - Long-term
+9. **CVE-MC-009**: Validate filenames for external tools
+10. **CVE-MC-010**: Pin dependency versions, add scanning
+
+---
+
+## Conclusion
+
+The MarkdownConverter application has a **HIGH RISK** threat profile due to the combination of:
+- Untrusted content rendering (markdown preview)
+- Direct system access (nodeIntegration)
+- Code execution capability (REPL)
+
+**Immediate action required on P0 items to reduce attack surface.**
+
+The fixes applied in this session (CSP, path traversal, UI accessibility) have reduced the risk profile, but the critical nodeIntegration issue requires significant refactoring.

.security-hardening/state.json

@@ -0,0 +1,27 @@
+{
+  "target": "MarkdownConverter Electron Application",
+  "status": "in_progress",
+  "depth": "comprehensive",
+  "compliance_frameworks": ["owasp"],
+  "current_step": 3,
+  "current_phase": 1,
+  "completed_steps": ["vulnerability-scan", "threat-modeling"],
+  "files_created": ["01-vulnerability-scan.md", "02-threat-model.md"],
+  "started_at": "2026-03-15T00:09:00.000Z",
+  "last_updated": "2026-03-15T00:25:00.000Z",
+  "findings_summary": {
+    "critical": 2,
+    "high": 3,
+    "medium": 3,
+    "low": 2,
+    "total": 10
+  },
+  "fixes_applied": {
+    "csp_external_cdns_removed": true,
+    "path_traversal_protection_added": true,
+    "aria_labels_added": true,
+    "focus_visible_styles_added": true,
+    "tab_close_button_resized": true,
+    "duplicate_font_size_fixed": true
+  }
+}

.ui-design/reviews/full-ui-review_20260315.md

@@ -0,0 +1,522 @@
+# Comprehensive UI Design Review - MarkdownConverter Electron Application
+
+## Executive Summary
+
+This review covers the UI design of the MarkdownConverter Electron application, analyzing visual design, usability, code quality, and performance across all UI files. The application has a solid foundation but has several areas requiring attention.
+
+---
+
+## 1. Visual Design Review
+
+### 1.1 Spacing & Layout Consistency
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Inconsistent padding values across files | Multiple CSS files | Standardize to 4px/8px base scale |
+| **Major** | Multiple reset declarations | `styles.css:1-5`, `styles-modern.css:42-47` | Consolidate resets into single file |
+| **Minor** | Tab padding varies between themes | `styles.css:36`, `styles-modern.css:101` | Use CSS variables for consistent padding |
+| **Minor** | Container padding inconsistency | `styles.css:17-21`, `styles-modern.css:63-69` | Define single container style |
+
+**Code Example - Duplicate Reset:**
+
+```css
+/* styles.css:1-5 */
+* {
+    margin: 0;
+    padding: 0;
+    box-sizing: border-box;
+}
+
+/* styles-modern.css:42-47 - DUPLICATE */
+* {
+  margin: 0;
+  padding: 0;
+  box-sizing: border-box;
+}
+```
+
+**Fix Recommendation:**
+```css
+/* Create a single base.css or remove from styles-modern.css */
+/* Use CSS variables for spacing scale */
+:root {
+  --space-1: 4px;
+  --space-2: 8px;
+  --space-3: 12px;
+  --space-4: 16px;
+  --space-5: 24px;
+  --space-6: 32px;
+}
+```
+
+### 1.2 Typography Consistency
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Font-family declared multiple times with different fallbacks | `styles.css:8`, `styles-modern.css:50`, `styles-concreteinfo.css:32` | Standardize font stack |
+| **Major** | Duplicate font-size declarations | `styles.css:228-230` | Remove duplicate |
+| **Minor** | Inconsistent line-height values | Multiple files | Create type scale variables |
+
+**Code Example - Duplicate font-size:**
+```css
+/* styles.css:226-230 */
+.preview-content {
+    max-width: none;
+    margin: 0;
+    padding: 20px 24px 24px 24px;
+    line-height: 1.6;
+    font-size: 15px;
+    font-size: 14px;  /* DUPLICATE - overwrites previous */
+}
+```
+
+**Fix Recommendation:**
+```css
+/* styles.css - Remove duplicate */
+.preview-content {
+    font-size: 14px;  /* Keep only one */
+    line-height: 1.6;
+}
+```
+
+### 1.3 Color Usage and Contrast Accessibility
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Critical** | Hardcoded colors instead of CSS variables | `styles.css:27-29`, `styles.css:37-38`, etc. | Use CSS custom properties |
+| **Major** | Inconsistent gray scale definitions | Multiple files define different grays | Consolidate to single palette |
+| **Minor** | Some contrast ratios may be insufficient | Status bar text colors | Verify WCAG 2.1 AA compliance |
+
+**Code Example - Hardcoded colors:**
+```css
+/* styles.css:27-29 */
+.tab-bar {
+    background: #f0f0f0;  /* Should use var(--gray-100) */
+    border-bottom: 1px solid #ddd;  /* Should use var(--gray-300) */
+}
+```
+
+**Fix Recommendation:**
+```css
+/* Use the existing palette from styles-modern.css */
+.tab-bar {
+    background: var(--gray-100, #f3f4f6);
+    border-bottom: 1px solid var(--gray-300, #d1d5db);
+}
+```
+
+### 1.4 Dark Mode Support Quality
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Dark theme selectors inconsistent | `styles.css` uses `body.theme-dark`, `styles-sidebar.css:108` uses `body[class*="dark"]` | Standardize selector pattern |
+| **Minor** | Missing dark theme support for some components | `.breadcrumb-bar`, command palette | Add dark mode variants |
+| **Suggestion** | Repetitive dark theme declarations | `styles-concreteinfo.css:362-425` | Use CSS custom properties for theming |
+
+**Code Example - Inconsistent selectors:**
+```css
+/* styles.css */
+body.theme-dark .tab-bar { ... }
+
+/* styles-sidebar.css */
+body[class*="dark"] .sidebar-icons { ... }
+```
+
+**Fix Recommendation:**
+```css
+/* Choose one pattern and apply consistently */
+/* Option 1: Class-based (recommended) */
+body.theme-dark .tab-bar,
+body.theme-dark .sidebar-icons { ... }
+
+/* Option 2: Attribute-based */
+body[data-theme="dark"] .tab-bar { ... }
+```
+
+---
+
+## 2. Usability Review
+
+### 2.1 Clickable/Tappable Areas
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Critical** | Tab close button too small (16x16px) | `styles.css:62-77` | Increase to minimum 24x24px |
+| **Major** | Sidebar icons at minimum size | `styles-sidebar.css:35-47` (36x36px) | Consider 40-44px for better touch |
+| **Minor** | Toolbar buttons at edge of minimum | `styles.css:120-131` (32x32px) | Acceptable for mouse, small for touch |
+
+**Code Example - Small close button:**
+```css
+/* styles.css:62-77 */
+.tab-close {
+    width: 16px;   /* TOO SMALL - below 24px minimum */
+    height: 16px;  /* TOO SMALL */
+}
+```
+
+**Fix Recommendation:**
+```css
+.tab-close {
+    width: 24px;
+    height: 24px;
+    border-radius: 4px;
+}
+
+/* Add touch-friendly hit area */
+.tab-close::before {
+    content: '';
+    position: absolute;
+    top: -4px;
+    left: -4px;
+    right: -4px;
+    bottom: -4px;
+}
+```
+
+### 2.2 Hover/Focus States
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Critical** | Missing focus-visible styles | All interactive elements | Add :focus-visible for keyboard navigation |
+| **Major** | No focus indicators on toolbar buttons | `styles.css:133-140` | Add visible focus ring |
+| **Minor** | Inconsistent hover transitions | Various components | Standardize transition duration |
+
+**Code Example - Missing focus styles:**
+```css
+/* styles.css:120-131 - No focus state */
+.toolbar button {
+    /* ... no focus style */
+}
+
+.toolbar button:hover {
+    background: #e0e0e0;
+    border-color: #ccc;
+}
+```
+
+**Fix Recommendation:**
+```css
+.toolbar button:focus-visible {
+    outline: 2px solid var(--primary-dark, #5661b3);
+    outline-offset: 2px;
+}
+
+.toolbar button:hover {
+    background: #e0e0e0;
+    border-color: #ccc;
+}
+```
+
+### 2.3 Loading and Error State Handling
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Generic error message without styling | `renderer.js:384-386`, `renderer.js:508-511` | Create styled error components |
+| **Minor** | No loading indicators for async operations | Sidebar panels | Add skeleton loaders or spinners |
+| **Minor** | `git-loading` class exists but minimal styling | `styles-sidebar.css:227` | Enhance with animation |
+
+**Code Example - Plain error display:**
+```javascript
+// renderer.js:384-386
+preview.innerHTML = '<p style="color: red; padding: 20px;">Error: Required libraries...';
+// Inline styles should be in CSS
+```
+
+**Fix Recommendation:**
+```css
+/* Add to styles.css */
+.preview-error {
+    display: flex;
+    flex-direction: column;
+    align-items: center;
+    justify-content: center;
+    padding: 40px 20px;
+    color: var(--ci-danger, #dc3545);
+    text-align: center;
+}
+
+.preview-error-icon {
+    font-size: 48px;
+    margin-bottom: 16px;
+}
+```
+
+### 2.4 Accessibility (ARIA, Semantic HTML)
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Critical** | Buttons without accessible labels | `index.html:31` (tab close), `index.html:33` (new tab) | Add aria-label |
+| **Critical** | SVG icons lack aria-hidden | All toolbar buttons | Add aria-hidden="true" |
+| **Major** | Missing role attributes on tabs | `index.html:29-33` | Add role="tablist", role="tab" |
+| **Major** | No skip links | `index.html` | Add skip to main content link |
+| **Minor** | Dialog missing aria-modal | Export dialogs | Add aria-modal="true" |
+
+**Code Example - Missing accessibility attributes:**
+```html
+<!-- index.html:31 - Current -->
+<button class="tab-close" title="Close tab">x</button>
+
+<!-- index.html:33 - Current -->
+<button class="new-tab-button" id="new-tab-btn" title="New tab">+</button>
+```
+
+**Fix Recommendation:**
+```html
+<!-- Improved with ARIA -->
+<div class="tab-bar" id="tab-bar" role="tablist" aria-label="Document tabs">
+    <div class="tab active" data-tab-id="1" role="tab" aria-selected="true" aria-controls="tab-content-1">
+        <span class="tab-title">Untitled</span>
+        <button class="tab-close" aria-label="Close tab" title="Close tab">×</button>
+    </div>
+    <button class="new-tab-button" id="new-tab-btn" aria-label="Create new tab" title="New tab">+</button>
+</div>
+
+<!-- SVG icons should have aria-hidden -->
+<button id="btn-bold" title="Bold (Ctrl+B)" aria-label="Bold">
+    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
+        ...
+    </svg>
+</button>
+```
+
+### 2.5 Keyboard Navigation
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Tab order may skip sidebar icons | Sidebar panel | Verify logical tab order |
+| **Minor** | No escape key handling for dialogs | Export dialogs | Add escape to close |
+| **Minor** | Find dialog lacks full keyboard support | `renderer.js:804-866` | Add Ctrl+F shortcut hint |
+
+---
+
+## 3. Code Quality Review
+
+### 3.1 CSS Organization & Naming
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | No clear CSS architecture | All CSS files | Adopt BEM or similar methodology |
+| **Major** | Overly generic class names | `.pane`, `.tab`, `.container` | Use more specific naming |
+| **Minor** | Mixed naming conventions | camelCase (`tabBar`), kebab-case (`tab-bar`) | Standardize to kebab-case |
+| **Minor** | Magic numbers | Various pixel values | Replace with spacing variables |
+
+### 3.2 CSS Specificity Issues
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Excessive use of `!important` | `styles.css:14` | Restructure to avoid |
+| **Major** | Deep selector nesting | Dark theme selectors | Flatten and use CSS variables |
+| **Minor** | ID selectors for styling | `styles.css:233-247` | Prefer class selectors |
+
+**Code Example - Problematic specificity:**
+```css
+/* styles.css:14 - Avoid !important */
+.hidden {
+    display: none !important;
+}
+
+/* styles.css:397-431 - Deep nesting */
+body.theme-dark #preview h1,
+body.theme-dark [id^="preview-"] h1,
+body.theme-dark .preview-content h1 {
+    color: #c9d1d9;
+    border-bottom-color: #21262d;
+}
+```
+
+**Fix Recommendation:**
+```css
+/* Use utility class pattern */
+[hidden] { display: none; }
+
+/* Use CSS custom properties for theming */
+.preview-content h1 {
+    color: var(--text-primary);
+    border-bottom-color: var(--border-color);
+}
+
+/* Theme applies variables */
+body.theme-dark {
+    --text-primary: #c9d1d9;
+    --border-color: #21262d;
+}
+```
+
+### 3.3 Reusable Style Definitions
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Repeated button styles | Multiple files | Create button component classes |
+| **Major** | Dialog styles duplicated | Export, batch, print preview dialogs | Create modal component |
+| **Minor** | Similar form field styles scattered | Export dialog inputs | Create form component |
+
+**Code Example - Duplicated button styles:**
+```css
+/* styles.css */
+.toolbar button { /* button styles */ }
+.tab-close { /* button styles */ }
+.new-tab-button { /* button styles */ }
+#export-dialog-close { /* button styles */ }
+
+/* styles-sidebar.css */
+.sidebar-icon { /* similar button styles */ }
+.sidebar-panel-close { /* similar button styles */ }
+```
+
+**Fix Recommendation:**
+```css
+/* Create button component system */
+.btn {
+    display: inline-flex;
+    align-items: center;
+    justify-content: center;
+    border: none;
+    cursor: pointer;
+    transition: all var(--transition-fast);
+}
+
+.btn--icon {
+    width: 32px;
+    height: 32px;
+    border-radius: var(--radius-md);
+}
+
+.btn--close {
+    font-size: 14px;
+    font-weight: bold;
+    border-radius: var(--radius-sm);
+}
+```
+
+### 3.4 Documentation
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Minor** | Limited CSS documentation | All CSS files | Add section comments |
+| **Minor** | No component documentation | Sidebar components | Add JSDoc-style comments |
+| **Suggestion** | No design tokens documentation | CSS variables | Create tokens documentation |
+
+---
+
+## 4. Performance Review
+
+### 4.1 CSS Optimization
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | Large CSS files (105KB main, 78KB modern) | `styles.css`, `styles-modern.css` | Split into smaller modules |
+| **Major** | Duplicate style definitions | Multiple files | Remove redundancies |
+| **Minor** | Unused styles likely present | Theme variations | Audit and remove unused |
+
+### 4.2 Asset Loading
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Major** | highlight.js CSS loaded synchronously | `index.html:14` | Load asynchronously or bundle |
+| **Minor** | Font files could be preloaded | `fonts.css` | Add preload links in HTML |
+| **Suggestion** | Consider CSS critical path | Above-the-fold styles | Inline critical CSS |
+
+**Code Example - Sync stylesheet loading:**
+```html
+<!-- index.html:14 - Blocks rendering -->
+<link rel="stylesheet" href="../node_modules/highlight.js/styles/default.css">
+```
+
+**Fix Recommendation:**
+```html
+<!-- Non-blocking load -->
+<link rel="stylesheet" href="../node_modules/highlight.js/styles/default.css" media="print" onload="this.media='all'">
+
+<!-- Or preload fonts -->
+<link rel="preload" href="../assets/fonts/Inter-Regular.woff2" as="font" type="font/woff2" crossorigin>
+```
+
+### 4.3 Animation Performance
+
+| Severity | Issue | Location | Recommendation |
+|----------|-------|----------|----------------|
+| **Minor** | Some transitions on expensive properties | `styles-modern.css:111-112` | Prefer transform/opacity |
+| **Suggestion** | Missing will-change hints | Complex animations | Add will-change for GPU hints |
+
+---
+
+## 5. Component-Specific Issues
+
+### 5.1 Tab System
+
+| File | Issues |
+|------|--------|
+| `styles.css:23-97` | Inconsistent active state styling, small close button |
+| `renderer.js:88-346` | Tab content created via innerHTML (XSS risk) |
+
+### 5.2 Sidebar
+
+| File | Issues |
+|------|--------|
+| `styles-sidebar.css` | Good structure but missing focus states |
+| `sidebar-manager.js` | Clean implementation, needs ARIA |
+
+### 5.3 Export Dialogs
+
+| File | Issues |
+|------|--------|
+| `styles.css:1060-1355` | Monolithic, should be component |
+| `index.html:171-331` | Complex nested structure needs semantic HTML |
+
+### 5.4 Welcome Screen
+
+| File | Issues |
+|------|--------|
+| `styles-welcome.css` | Minimal styles, good foundation |
+| Missing hover states for keyboard focus | Add :focus-visible |
+
+---
+
+## 6. Prioritized Fix Recommendations
+
+### Critical (Immediate)
+
+1. **Add missing ARIA attributes** to all interactive elements
+2. **Increase tab close button size** to minimum 24x24px
+3. **Add focus-visible styles** for keyboard navigation
+4. **Fix duplicate font-size declaration** in `.preview-content`
+
+### Major (Next Sprint)
+
+1. **Consolidate CSS resets** into single location
+2. **Create button component system** with variants
+3. **Standardize dark theme selectors** across all files
+4. **Replace hardcoded colors** with CSS variables
+5. **Create modal/dialog component** to reduce duplication
+
+### Minor (Future)
+
+1. **Document CSS architecture** and naming conventions
+2. **Audit and remove unused styles**
+3. **Add loading state components** (skeletons, spinners)
+4. **Implement CSS module splitting** for better performance
+
+---
+
+## 7. Summary Statistics
+
+| Category | Critical | Major | Minor | Suggestions |
+|----------|----------|-------|-------|-------------|
+| Visual Design | 1 | 5 | 4 | 1 |
+| Usability | 3 | 4 | 4 | 0 |
+| Code Quality | 0 | 6 | 4 | 1 |
+| Performance | 0 | 3 | 2 | 2 |
+| **Total** | **4** | **18** | **14** | **4** |
+
+---
+
+## Conclusion
+
+The MarkdownConverter application has a functional UI with good visual variety through its theme system. However, there are significant opportunities for improvement in:
+
+1. **Accessibility** - Critical for users with disabilities
+2. **Code organization** - Reduce CSS duplication and improve maintainability
+3. **Component consistency** - Standardize interactive element sizing and states
+4. **Performance** - Optimize CSS loading and reduce bundle size
+
+Addressing the Critical and Major issues will significantly improve both user experience and code maintainability.

.ui-design/reviews/review_state.json

@@ -0,0 +1,17 @@
+{
+  "review_id": "full-ui-review_20260315",
+  "target": "src/ (Entire UI Directory)",
+  "focus_areas": ["visual", "usability", "code", "performance"],
+  "context": "comprehensive",
+  "platform": "desktop",
+  "status": "complete",
+  "started_at": "2026-03-15T00:09:00.000Z",
+  "completed_at": "2026-03-15T00:12:00.000Z",
+  "issues_found": 40,
+  "severity_counts": {
+    "critical": 4,
+    "major": 18,
+    "minor": 14,
+    "suggestion": 4
+  }
+}

.vscode/launch.json

@@ -0,0 +1,48 @@
+{
+  "version": "0.2.0",
+  "configurations": [
+    {
+      "name": "Debug Main Process",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron",
+      "windows": {
+        "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron.cmd"
+      },
+      "args": ["."],
+      "outputCapture": "std",
+      "env": {
+        "NODE_ENV": "development"
+      }
+    },
+    {
+      "name": "Debug Renderer Process",
+      "type": "chrome",
+      "request": "attach",
+      "port": 9222,
+      "webRoot": "${workspaceFolder}/src",
+      "timeout": 30000
+    },
+    {
+      "name": "Debug Main + Renderer",
+      "type": "node",
+      "request": "launch",
+      "cwd": "${workspaceFolder}",
+      "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron",
+      "windows": {
+        "runtimeExecutable": "${workspaceFolder}/node_modules/.bin/electron.cmd"
+      },
+      "args": [".", "--remote-debugging-port=9222"],
+      "outputCapture": "std",
+      "env": {
+        "NODE_ENV": "development"
+      },
+      "serverReadyAction": {
+        "pattern": "listening on port ([0-9]+)",
+        "uriFormat": "http://localhost:%s",
+        "action": "debugWithChrome"
+      }
+    }
+  ]
+}

AGENTS.md

@@ -0,0 +1,25 @@
+# Repository Guidelines
+
+## Project Structure & Module Organization
+Core application code lives in `src/`. Use `src/main.js` for the Electron main process, `src/preload.js` for the preload bridge, and `src/renderer.js` plus `src/editor/`, `src/sidebar/`, `src/repl/`, and `src/utils/` for renderer-side features. Electron adapter code is in `src/adapters/electron/`. Reusable markdown/document templates live in `src/templates/`. Static assets and icons are in `assets/`. Tests are in `tests/`, and build output goes to `dist/`.
+
+## Build, Test, and Development Commands
+- `npm start`: launch the Electron app locally.
+- `npm test`: run the Jest suite once.
+- `npm run test:watch`: rerun tests during local development.
+- `npm run test:coverage`: generate coverage output.
+- `npm run lint` / `npm run lint:fix`: check or fix ESLint issues in `src` and `tests`.
+- `npm run format` / `npm run format:check`: apply or verify Prettier formatting.
+- `npm run build:linux`, `npm run build:win`, `npm run build:mac`: create platform packages with `electron-builder`.
+
+## Coding Style & Naming Conventions
+This repo uses Prettier and ESLint. Follow `.prettierrc`: 2-space indentation, single quotes, semicolons, trailing commas where valid in ES5, and a 100-character line width. Prefer `camelCase` for variables/functions, `PascalCase` for classes, and kebab-case for file names only when already established. Keep module boundaries clear: UI logic in renderer modules, OS/file-system work behind Electron IPC and adapters.
+
+## Testing Guidelines
+Tests use Jest with `jest-environment-jsdom`. Add new tests under `tests/` with `*.test.js` names, mirroring the feature area when possible, for example `tests/sidebar.test.js` or `tests/print-preview.test.js`. Update or add regression tests for renderer behavior, preload APIs, and utility helpers when fixing bugs. Run `npm test` before opening a PR; use `npm run test:coverage` for larger refactors.
+
+## Commit & Pull Request Guidelines
+Recent history follows Conventional Commit prefixes such as `feat:`, `fix:`, and `refactor:`. Keep subjects short and imperative, for example `fix: guard modal cleanup on close`. PRs should describe the user-visible change, note test coverage, link any related issue, and include screenshots or GIFs for UI changes.
+
+## Security & Configuration Tips
+Do not bypass preload boundaries or introduce direct `eval`/dynamic code paths; ESLint already treats these as errors. Export and conversion features depend on external tools such as Pandoc, FFmpeg, ImageMagick, and LibreOffice, so document any new runtime dependency in `README.md` and packaging config.

README.md

@@ -162,4 +162,4 @@ Amit Haridas (amit.wh@gmail.com)
 
 ## Version
 
-v3.0.0
+v4.1.0

docs/THREAT_MODEL.md

@@ -0,0 +1,866 @@
+# MarkdownConverter - STRIDE Threat Model Analysis
+
+**Version:** 4.1.0
+**Date:** 2026-03-15
+**Methodology:** STRIDE + MITRE ATT&CK Mapping
+**Analyst:** Security Assessment Team
+
+---
+
+## Executive Summary
+
+This threat model analyzes the MarkdownConverter Electron application using the STRIDE methodology. The assessment identified **10 critical vulnerabilities** with CVSS scores ranging from 3.5 to 9.6. The most severe threats involve insecure Electron configuration (CVE-MC-001) and arbitrary code execution via REPL (CVE-MC-002), which could allow complete system compromise.
+
+**Risk Summary:**
+| Severity | Count | Total CVSS Impact |
+|----------|-------|-------------------|
+| Critical (9.0+) | 2 | 18.9 |
+| High (7.0-8.9) | 3 | 23.3 |
+| Medium (5.0-6.9) | 3 | 17.3 |
+| Low (<5.0) | 2 | 7.9 |
+
+---
+
+## 1. System Architecture Overview
+
+### 1.1 Application Components
+
+```
++------------------------------------------------------------------+
+|                    MarkdownConverter v4.0.0                       |
++------------------------------------------------------------------+
+|                                                                   |
+|  +------------------+     +------------------+                    |
+|  |   Main Process   |<--->|  Renderer Process|                    |
+|  |    (Node.js)     |     |   (Chromium)     |                    |
+|  +------------------+     +------------------+                    |
+|          |                        |                               |
+|          | IPC Channels           |                               |
+|          v                        v                               |
+|  +------------------+     +------------------+                    |
+|  |   preload.js     |     |   renderer.js    |                    |
+|  | (Bridge Layer)   |     | (UI Logic)       |                    |
+|  +------------------+     +------------------+                    |
+|          |                        |                               |
+|          v                        v                               |
+|  +--------------------------------------------------+             |
+|  |              External Tools                       |             |
+|  | Pandoc | FFmpeg | ImageMagick | LibreOffice      |             |
+|  +--------------------------------------------------+             |
+|                                                                   |
++------------------------------------------------------------------+
+                              |
+                              v
++------------------------------------------------------------------+
+|                    External Services                              |
+|  - plantuml.com (diagram rendering)                              |
+|  - cdn.jsdelivr.net (scripts)                                    |
+|  - cdnjs.cloudflare.com (styles)                                 |
++------------------------------------------------------------------+
+```
+
+### 1.2 Data Flow Diagram (Level 1)
+
+```
+                              TRUST BOUNDARY
+                                    |
+    +-----------+                   |                   +-----------+
+    |   User    |                   |                   |  System   |
+    | (Author)  |------------------>|------------------>|   Files   |
+    +-----------+   Markdown        |   File I/O        +-----------+
+                    Content         |
+                                    |
+                    +---------------+---------------+
+                    |                               |
+                    v                               v
+            +---------------+               +---------------+
+            |    Editor     |               |   Preview     |
+            | (CodeMirror)  |               |  (Rendered)   |
+            +---------------+               +---------------+
+                    |                               ^
+                    |    Sanitization               |
+                    |    (DOMPurify)                |
+                    v                               |
+            +---------------+                       |
+            |   Renderer    |-----------------------+
+            |   Process     |  HTML/SVG
+            +---------------+
+                    |
+                    | IPC (Whitelisted Channels)
+                    v
+            +---------------+               +-----------+
+            |    Main       |-------------->|  Pandoc   |
+            |   Process     |  execFile     |  FFmpeg   |
+            |   (Node.js)   |               |  etc.     |
+            +---------------+               +-----------+
+                    |
+                    | HTTPS
+                    v
+            +---------------+
+            |  PlantUML     |
+            |  Server       |
+            | (External)    |
+            +---------------+
+```
+
+### 1.3 Trust Boundaries
+
+```
++============================================================================+
+||                     TRUST BOUNDARY 1: User <-> Application               ||
+||  - User input (markdown content) is UNTRUSTED                            ||
+||  - File paths from dialogs are PARTIALLY TRUSTED                         ||
++============================================================================+
+                                    |
+                                    v
++============================================================================+
+||                     TRUST BOUNDARY 2: Renderer <-> Main Process          ||
+||  - IPC communication via preload.js                                       ||
+||  - CRITICAL: nodeIntegration=true bypasses isolation                      ||
++============================================================================+
+                                    |
+                                    v
++============================================================================+
+||                     TRUST BOUNDARY 3: Application <-> System             ||
+||  - External tool execution (Pandoc, FFmpeg, etc.)                         ||
+||  - File system access                                                     ||
++============================================================================+
+                                    |
+                                    v
++============================================================================+
+||                     TRUST BOUNDARY 4: Application <-> Internet           ||
+||  - PlantUML server (https://www.plantuml.com)                            ||
+||  - CDN resources (jsdelivr, cdnjs)                                        ||
++============================================================================+
+```
+
+---
+
+## 2. STRIDE Analysis
+
+### 2.1 Spoofing
+
+| ID | Threat | Description | CVE | CVSS |
+|----|--------|-------------|-----|------|
+| S-01 | **PlantUML Server Spoofing** | Application sends diagram content to external PlantUML server. MITM or compromised server could return malicious SVG content. | CVE-MC-007 | 5.3 |
+| S-02 | **CDN Compromise** | Scripts loaded from cdn.jsdelivr.net and styles from cdnjs.cloudflare.com could be compromised in supply chain attack. | - | 6.5 |
+
+**Attack Tree - S-01 PlantUML Data Exfiltration:**
+
+```
+GOAL: Exfiltrate sensitive data via PlantUML rendering
+│
+├── [1] Intercept network traffic (MITM)
+│   ├── [1.1] Exploit weak TLS implementation
+│   └── [1.1] DNS hijacking
+│
+├── [2] Compromise PlantUML server
+│   ├── [2.1] Server breach
+│   └── [2.2] Supply chain compromise
+│
+└── [3] Inject malicious SVG response
+    ├── [3.1] XSS via SVG onload
+    └── [3.2] Data exfiltration via image src
+```
+
+### 2.2 Tampering
+
+| ID | Threat | Description | CVE | CVSS |
+|----|--------|-------------|-----|------|
+| T-01 | **Markdown Content Tampering** | XSS in markdown rendering could modify rendered content or inject malicious scripts. | CVE-MC-003 | 8.0 |
+| T-02 | **File Tampering via Path Traversal** | Missing path validation could allow writing to arbitrary locations. | CVE-MC-004 | 7.8 |
+| T-03 | **REPL Code Injection** | Arbitrary code execution via REPL feature allows system modification. | CVE-MC-002 | 9.3 |
+
+**Attack Tree - T-03 REPL Code Injection:**
+
+```
+GOAL: Achieve arbitrary code execution via REPL
+│
+├── [1] User opens malicious markdown file
+│   ├── [1.1] Phishing/social engineering
+│   └── [1.2] Malicious file from untrusted source
+│
+├── [2] Malicious code block rendered in preview
+│   ├── [2.1] JavaScript code block
+│   ├── [2.2] Python code block
+│   └── [2.3] Bash/Shell code block
+│
+├── [3] User clicks "Run" button
+│
+└── [4] Code executed on main process
+    ├── [4.1] File system access
+    ├── [4.2] Process execution
+    └── [4.3] Network access
+        └── [4.3.1] Data exfiltration
+        └── [4.3.2] C2 communication
+```
+
+### 2.3 Repudiation
+
+| ID | Threat | Description | CVE | CVSS |
+|----|--------|-------------|-----|------|
+| R-01 | **Missing Audit Logging** | No logging of security-relevant events (file access, code execution, exports). | - | 4.0 |
+| R-02 | **REPL Execution No Audit Trail** | Code executed via REPL leaves no persistent audit log. | CVE-MC-002 | 5.0 |
+
+### 2.4 Information Disclosure
+
+| ID | Threat | Description | CVE | CVSS |
+|----|--------|-------------|-----|------|
+| I-01 | **Path Disclosure in Error Messages** | Error messages may expose absolute file paths. Partially mitigated by `sanitizeErrorMessage()`. | - | 4.5 |
+| I-02 | **PlantUML Data Leakage** | Diagram content sent to external server could contain sensitive information. | CVE-MC-007 | 5.3 |
+| I-03 | **CSP Allows External Connections** | Weak CSP allows data exfiltration via `connect-src 'self' https://www.plantuml.com`. | CVE-MC-005 | 7.5 |
+
+**Data Flow - Information Disclosure via PlantUML:**
+
+```
++-------------+     Encoded Diagram      +------------------+
+|  Renderer   | ----------------------> | www.plantuml.com |
+|  Process    |   (~h encoded)          |   (External)     |
++-------------+                         +------------------+
+       |                                        |
+       | Sensitive data in diagram:             |
+       | - Architecture details                 |
+       | - Database schemas                     |
+       | - API endpoints                        |
+       | - Class names/relationships            |
+       v                                        v
++-------------+                         +-------------+
+|  Attacker   | <--- Network Capture -- |  Network    |
+|  (MITM)     |                         |  Traffic    |
++-------------+                         +-------------+
+```
+
+### 2.5 Denial of Service
+
+| ID | Threat | Description | CVE | CVSS |
+|----|--------|-------------|-----|------|
+| D-01 | **REPL Resource Exhaustion** | Code execution has 10s timeout but could consume CPU/memory. | CVE-MC-002 | 4.5 |
+| D-02 | **Large File Processing** | Files up to 50MB allowed, could cause memory exhaustion during conversion. | - | 5.0 |
+| D-03 | **Infinite Loop in Markdown** | Malicious markdown could cause rendering loops. | - | 4.0 |
+
+### 2.6 Elevation of Privilege
+
+| ID | Threat | Description | CVE | CVSS |
+|----|--------|-------------|-----|------|
+| E-01 | **Insecure Electron Configuration** | `nodeIntegration: true` + `contextIsolation: false` allows full Node.js access from renderer. | CVE-MC-001 | 9.6 |
+| E-02 | **XSS to RCE Chain** | XSS vulnerability combined with E-01 enables remote code execution. | CVE-MC-003 + CVE-MC-001 | 9.8 |
+| E-03 | **External Tool Command Injection** | While using `execFile`, improper input validation could still pose risks. | CVE-MC-009 | 4.4 |
+| E-04 | **Inconsistent Window Security** | PDF export windows use insecure settings (nodeIntegration: true). | CVE-MC-006 | 6.5 |
+
+**Attack Tree - E-01/E-02 XSS to RCE Chain:**
+
+```
+GOAL: Remote Code Execution via XSS -> RCE Chain
+│
+├── [1] Inject malicious script (XSS)
+│   ├── [1.1] Via malicious markdown file
+│   │   ├── HTML injection
+│   │   ├── SVG with script
+│   │   └── DOMPurify bypass
+│   │
+│   └── [1.2] Via PlantUML SVG response
+│       └── Compromised server returns malicious SVG
+│
+├── [2] Execute in renderer context
+│   └── [2.1] Script runs with nodeIntegration=true
+│       ├── Direct require() access
+│       ├── child_process.exec()
+│       └── fs module access
+│
+└── [3] Achieve RCE
+    ├── [3.1] Execute system commands
+    ├── [3.2] Read/write arbitrary files
+    ├── [3.3] Install persistence mechanisms
+    └── [3.4] Lateral movement
+```
+
+---
+
+## 3. Attack Scenarios
+
+### 3.1 Scenario: Malicious Markdown Document (Critical)
+
+**Attack Chain:**
+
+```
+1. Attacker creates malicious.md containing:
+   - Embedded JavaScript in markdown
+   - Malicious code blocks (JavaScript/Python/Bash)
+
+2. Victim opens file in MarkdownConverter
+
+3. XSS payload executes due to:
+   - CVE-MC-003: Potential XSS in markdown rendering
+   - CVE-MC-001: nodeIntegration=true allows Node.js access
+
+4. Payload executes system commands:
+   - Exfiltrates sensitive files
+   - Installs backdoor
+   - Establishes persistence
+
+5. Impact: Complete system compromise
+```
+
+**MITRE ATT&CK Mapping:**
+
+| Tactic | Technique | ID | Description |
+|--------|-----------|-----|-------------|
+| Initial Access | Phishing | T1566 | Malicious file via email |
+| Execution | User Execution | T1204 | Victim opens malicious file |
+| Execution | Command/Scripting | T1059 | JavaScript/Python execution |
+| Persistence | Registry Run Keys | T1547 | Establish persistence |
+| Collection | Data from Local System | T1005 | File exfiltration |
+| Exfiltration | Exfiltration Over C2 | T1041 | Data sent to attacker |
+
+### 3.2 Scenario: REPL Code Execution (Critical)
+
+**Attack Chain:**
+
+```
+1. Social engineering: Attacker convinces user to:
+   - Open a "configuration guide" markdown file
+   - Run the code examples to "verify setup"
+
+2. Markdown contains malicious code blocks:
+   ```javascript
+   const fs = require('fs');
+   const https = require('https');
+   // Exfiltrate SSH keys
+   ```
+
+3. User clicks "Run" button on code block
+
+4. Code executes via 'execute-code' IPC handler:
+   - CVE-MC-002: Arbitrary code execution via REPL
+   - No sandboxing or permission checks
+
+5. Impact: Credential theft, data exfiltration
+```
+
+**MITRE ATT&CK Mapping:**
+
+| Tactic | Technique | ID | Description |
+|--------|-----------|-----|-------------|
+| Initial Access | Phishing | T1566 | Social engineering |
+| Execution | Command/Scripting | T1059.004 | Bash execution |
+| Execution | Command/Scripting | T1059.007 | JavaScript/Node execution |
+| Credential Access | Credentials from Files | T1083 | SSH key theft |
+| Exfiltration | Exfiltration Over Web Service | T1567 | HTTPS exfiltration |
+
+### 3.3 Scenario: PlantUML Data Exfiltration (Medium)
+
+**Attack Chain:**
+
+```
+1. User creates architecture diagram in PlantUML:
+   - Contains sensitive system design
+   - Database schemas
+   - API endpoints
+
+2. Renderer encodes and sends to www.plantuml.com:
+   - CVE-MC-007: Data sent to external server
+
+3. Attacker (MITM or compromised server):
+   - Captures diagram content
+   - Extracts sensitive information
+
+4. Impact: Intellectual property theft, reconnaissance
+```
+
+### 3.4 Scenario: PDF Export Window Exploitation (Medium)
+
+**Attack Chain:**
+
+```
+1. User exports document to PDF
+
+2. Hidden PDF export window created with:
+   - CVE-MC-006: nodeIntegration: true
+   - CVE-MC-008: contextIsolation: false
+
+3. If malicious content in document:
+   - Script execution in PDF window
+   - Access to Node.js APIs
+
+4. Impact: Code execution during export process
+```
+
+---
+
+## 4. Risk Matrix & Prioritization
+
+### 4.1 Vulnerability Risk Matrix
+
+```
+                              IMPACT
+                    Low         Medium         High          Critical
+                  (1-3)        (4-6)          (7-8)          (9-10)
+              +------------+------------+--------------+-------------+
+    High      | CVE-MC-010 | CVE-MC-007 | CVE-MC-005   | CVE-MC-001  |
+   (0.7-1.0)  |   3.5      |   5.3      |    7.5       |    9.6      |
+              |  DEPENDENCY |  INFOSEC   |    CSP       |   CONFIG    |
+              +------------+------------+--------------+-------------+
+              |            | CVE-MC-006 | CVE-MC-003   | CVE-MC-002  |
+LIKELIHOOD    |            |   6.5      |    8.0       |    9.3      |
+   (0.4-0.6)  |            |  PDF-WIN   |    XSS       |    REPL     |
+              +------------+------------+--------------+-------------+
+    Medium    |            | CVE-MC-008 | CVE-MC-004   |             |
+   (0.2-0.4)  |            |   5.5      |    7.8       |             |
+              |            |  INCONSIST |  PATH-TRAV   |             |
+              +------------+------------+--------------+-------------+
+    Low       |            |            | CVE-MC-009   |             |
+   (0-0.2)    |            |            |    4.4       |             |
+              |            |            |  CMD-EXEC    |             |
+              +------------+------------+--------------+-------------+
+```
+
+### 4.2 Prioritized Remediation List
+
+| Priority | CVE | Vulnerability | CVSS | Effort | Risk Reduction |
+|----------|-----|---------------|------|--------|----------------|
+| P0 | CVE-MC-001 | Insecure Electron Config | 9.6 | Medium | Critical |
+| P0 | CVE-MC-002 | REPL Code Execution | 9.3 | High | Critical |
+| P1 | CVE-MC-003 | XSS in Markdown | 8.0 | Medium | High |
+| P1 | CVE-MC-004 | Path Traversal | 7.8 | Low | High |
+| P1 | CVE-MC-005 | Weak CSP | 7.5 | Medium | High |
+| P2 | CVE-MC-006 | PDF Window Config | 6.5 | Low | Medium |
+| P2 | CVE-MC-008 | Inconsistent Settings | 5.5 | Low | Medium |
+| P2 | CVE-MC-007 | PlantUML Exfiltration | 5.3 | Medium | Medium |
+| P3 | CVE-MC-009 | External Tool Execution | 4.4 | Low | Low |
+| P3 | CVE-MC-010 | Dependency Versioning | 3.5 | Low | Low |
+
+### 4.3 Risk Score Calculation
+
+```
+Overall Application Risk Score: 7.8 (HIGH)
+
+Calculation:
+- Weighted by exploitability and impact
+- P0 issues weighted 3x
+- P1 issues weighted 2x
+- P2 issues weighted 1x
+- P3 issues weighted 0.5x
+
+Risk = (9.6*3 + 9.3*3 + 8.0*2 + 7.8*2 + 7.5*2 + 6.5 + 5.5 + 5.3 + 4.4*0.5 + 3.5*0.5) / 17
+     = (28.8 + 27.9 + 16.0 + 15.6 + 15.0 + 6.5 + 5.5 + 5.3 + 2.2 + 1.75) / 17
+     = 124.55 / 17
+     = 7.33 (adjusted to 7.8 with environmental factors)
+```
+
+---
+
+## 5. Business Impact Analysis
+
+### 5.1 Impact Categories
+
+| Category | Description | Affected CVEs | Impact Level |
+|----------|-------------|---------------|--------------|
+| **Data Confidentiality** | Unauthorized access to sensitive documents | CVE-MC-001,002,003,007 | Critical |
+| **Data Integrity** | Modification of documents or system files | CVE-MC-001,002,004 | Critical |
+| **System Availability** | Application or system unavailability | CVE-MC-002,009 | Medium |
+| **Compliance** | Regulatory violations (GDPR, HIPAA) | CVE-MC-001,002,007 | High |
+| **Reputation** | Trust damage from security incidents | All CVEs | High |
+| **Financial** | Direct costs from breaches | CVE-MC-001,002,003 | Critical |
+
+### 5.2 Business Impact by Attack Type
+
+#### Complete System Compromise (CVE-MC-001 + CVE-MC-002)
+```
+Financial Impact:
+- Incident response: $50,000 - $200,000
+- Data breach notification: $100,000+
+- Regulatory fines: Up to 4% annual revenue (GDPR)
+- Legal fees: $100,000 - $500,000
+- Business disruption: $10,000/day
+
+Reputational Impact:
+- Customer trust erosion
+- Market share loss
+- Brand damage
+
+Estimated Total: $500,000 - $5,000,000+
+```
+
+#### Data Exfiltration via PlantUML (CVE-MC-007)
+```
+Financial Impact:
+- Intellectual property theft
+- Competitive disadvantage
+- Remediation costs: $20,000 - $50,000
+
+Reputational Impact:
+- Customer concerns about data handling
+- Potential contract violations
+
+Estimated Total: $50,000 - $500,000
+```
+
+#### XSS Attack (CVE-MC-003)
+```
+Financial Impact:
+- Session hijacking remediation
+- Credential reset costs
+- Monitoring enhancement
+
+Estimated Total: $10,000 - $100,000
+```
+
+### 5.3 Risk Tolerance Matrix
+
+| Asset | Criticality | Current Risk | Tolerance | Gap |
+|-------|-------------|--------------|-----------|-----|
+| User Documents | High | Critical | Low | **HIGH** |
+| System Integrity | Critical | Critical | Very Low | **CRITICAL** |
+| User Credentials | Critical | High | Very Low | **HIGH** |
+| Application Availability | Medium | Medium | Medium | Low |
+| Network Communication | Medium | Medium | Low | Medium |
+
+---
+
+## 6. MITRE ATT&CK Framework Mapping
+
+### 6.1 Complete Technique Mapping
+
+| Tactic | Technique | ID | CVE Reference | Detection | Mitigation |
+|--------|-----------|-----|---------------|-----------|------------|
+| **Initial Access** |
+| | Phishing | T1566 | CVE-MC-003 | Email filtering | User training |
+| | Valid Accounts | T1078 | N/A | Auth logging | MFA |
+| **Execution** |
+| | Command/Scripting Interpreter | T1059 | CVE-MC-002 | Process monitoring | Disable REPL |
+| | JavaScript | T1059.007 | CVE-MC-001,003 | CSP violations | Enable contextIsolation |
+| | Python | T1059.006 | CVE-MC-002 | Process monitoring | Sandboxing |
+| | Bash | T1059.004 | CVE-MC-002 | Process monitoring | Input validation |
+| **Persistence** |
+| | Registry Run Keys | T1547.001 | Post-CVE-MC-001 | Registry monitoring | Principle of least privilege |
+| | Scheduled Task | T1053 | Post-CVE-MC-001 | Task monitoring | Application hardening |
+| **Defense Evasion** |
+| | Obfuscated Files | T1027 | CVE-MC-003 | Content inspection | Strict CSP |
+| **Credential Access** |
+| | Credentials from Files | T1083 | CVE-MC-002 | File access monitoring | Isolate secrets |
+| **Discovery** |
+| | File and Directory Discovery | T1083 | CVE-MC-001,002 | File monitoring | Sandbox |
+| | System Information Discovery | T1082 | CVE-MC-002 | Process monitoring | Disable REPL |
+| **Collection** |
+| | Data from Local System | T1005 | CVE-MC-002 | DLP | Access controls |
+| **Command and Control** |
+| | Application Layer Protocol | T1071 | CVE-MC-007 | Network monitoring | Disable external services |
+| **Exfiltration** |
+| | Exfiltration Over Web Service | T1567 | CVE-MC-007 | Network monitoring | Block external connections |
+| | Exfiltration Over C2 | T1041 | Post-exploitation | EDR | Network segmentation |
+
+### 6.2 Attack Flow Diagram
+
+```
++------------------+     +------------------+     +------------------+
+|   INITIAL        |     |   EXECUTION      |     |   PERSISTENCE    |
+|   ACCESS         |     |                  |     |                  |
+|                  |     |                  |     |                  |
+|  T1566 Phishing  |---->| T1059.007 JS     |---->| T1547.001 Reg    |
+|  T1204 User Exec |     | T1059.004 Bash   |     | T1053 Sched Task |
+|                  |     | T1059.006 Python |     |                  |
++------------------+     +------------------+     +------------------+
+                                |
+                                v
++------------------+     +------------------+     +------------------+
+|   COLLECTION     |<----|   DISCOVERY      |     |   C2             |
+|                  |     |                  |     |                  |
+| T1005 Local Data |     | T1083 File Disc  |     | T1071 HTTPS      |
+| T1083 Creds File |     | T1082 Sys Info   |     |                  |
++------------------+     +------------------+     +------------------+
+        |
+        v
++------------------+
+|   EXFILTRATION   |
+|                  |
+| T1567 Web Service|
+| T1041 Over C2    |
++------------------+
+```
+
+---
+
+## 7. Security Requirements & Mitigations
+
+### 7.1 Critical Mitigations (P0)
+
+#### CVE-MC-001: Insecure Electron Configuration
+
+**Current State:**
+```javascript
+// main.js:328-331
+webPreferences: {
+  nodeIntegration: true,
+  contextIsolation: false,
+  spellcheck: true
+}
+```
+
+**Required Changes:**
+```javascript
+webPreferences: {
+  nodeIntegration: false,      // REQUIRED
+  contextIsolation: true,       // REQUIRED
+  sandbox: true,                // RECOMMENDED
+  spellcheck: true
+}
+```
+
+**Migration Path:**
+1. Update preload.js to expose all required APIs
+2. Update renderer.js to use exposed APIs instead of require()
+3. Test all functionality
+4. Deploy in stages
+
+#### CVE-MC-002: REPL Code Execution
+
+**Mitigation Options:**
+
+| Option | Security | Usability | Effort |
+|--------|----------|-----------|--------|
+| Disable REPL entirely | Highest | None | Low |
+| Sandbox with restricted permissions | High | High | High |
+| Add execution confirmation dialog | Medium | High | Low |
+| Require admin password | Medium | Medium | Medium |
+| Log all executions | Low | High | Low |
+
+**Recommended Approach:**
+1. Add user confirmation dialog with code preview
+2. Implement execution sandboxing (Docker/container)
+3. Add audit logging
+4. Restrict available modules
+
+### 7.2 High Priority Mitigations (P1)
+
+#### CVE-MC-003: XSS in Markdown
+
+**Current Mitigations:**
+- DOMPurify sanitization
+
+**Additional Required:**
+```javascript
+// Enhanced DOMPurify configuration
+const purifyConfig = {
+  ALLOWED_TAGS: [...],
+  ALLOWED_ATTR: [...],
+  FORBID_TAGS: ['script', 'iframe', 'object', 'embed'],
+  FORBID_ATTR: ['onerror', 'onload', 'onclick'],
+  ADD_ATTR: ['target'],
+  FORCE_BODY: true
+};
+```
+
+#### CVE-MC-005: Weak CSP
+
+**Current CSP:**
+```
+default-src 'self';
+script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net;
+style-src 'self' 'unsafe-inline' https://cdnjs.cloudflare.com;
+img-src 'self' data: blob: file:;
+font-src 'self' data:;
+connect-src 'self' https://www.plantuml.com;
+```
+
+**Recommended CSP:**
+```
+default-src 'self';
+script-src 'self';
+style-src 'self';
+img-src 'self' data:;
+font-src 'self';
+connect-src 'self';
+frame-src 'none';
+object-src 'none';
+base-uri 'self';
+form-action 'self';
+```
+
+**Note:** This requires:
+- Bundling all dependencies locally
+- Removing PlantUML server dependency (use local rendering)
+- Removing unsafe-inline and unsafe-eval
+
+### 7.3 Medium Priority Mitigations (P2)
+
+#### CVE-MC-006/008: Window Security Consistency
+
+**Affected Windows:**
+- PDF export window (main.js:2579-2585)
+- Hidden conversion window (main.js:3263-3268)
+
+**Fix:**
+```javascript
+webPreferences: {
+  nodeIntegration: false,
+  contextIsolation: true,
+  sandbox: true,
+  preload: path.join(__dirname, 'preload-pdf.js')
+}
+```
+
+#### CVE-MC-007: PlantUML Data Exfiltration
+
+**Options:**
+1. Use local PlantUML JAR file
+2. Use PlantUML npm package
+3. Add warning before sending to external server
+4. Allow configuration of PlantUML server URL
+
+---
+
+## 8. Attack Tree Summary
+
+### 8.1 Primary Attack Tree - Full System Compromise
+
+```
+GOAL: Full System Compromise via MarkdownConverter
+│
+├── [BRANCH A] Exploit CVE-MC-001 (nodeIntegration)
+│   │
+│   ├── [A.1] XSS via malicious markdown
+│   │   ├── [A.1.1] HTML injection
+│   │   ├── [A.1.2] SVG script injection
+│   │   └── [A.1.3] DOMPurify bypass
+│   │
+│   ├── [A.2] Compromised CDN script
+│   │   ├── [A.2.1] jsdelivr compromise
+│   │   └── [A.2.2] cdnjs compromise
+│   │
+│   └── [A.3] PlantUML SVG injection
+│       └── [A.3.1] Compromised plantuml.com
+│
+├── [BRANCH B] Exploit CVE-MC-002 (REPL)
+│   │
+│   ├── [B.1] Social engineering
+│   │   ├── [B.1.1] Malicious tutorial document
+│   │   └── [B.1.2] Phishing with "config file"
+│   │
+│   └── [B.2] Code execution
+│       ├── [B.2.1] JavaScript (Node.js)
+│       ├── [B.2.2] Python
+│       └── [B.2.3] Bash/Shell
+│
+└── [BRANCH C] Chain Exploits
+    │
+    ├── [C.1] XSS -> RCE (CVE-MC-003 + CVE-MC-001)
+    │   └── Impact: CVSS 9.8
+    │
+    ├── [C.2] Path Traversal -> Privilege Escalation
+    │   └── Impact: CVSS 8.5
+    │
+    └── [C.3] PlantUML -> XSS -> RCE
+        └── Impact: CVSS 9.1
+```
+
+### 8.2 Attack Success Probability
+
+| Attack Path | Complexity | Privileges Required | User Interaction | Probability |
+|-------------|------------|---------------------|------------------|-------------|
+| A.1 XSS->RCE | Low | None | Required | 75% |
+| A.2 CDN Compromise | High | None | None | 15% |
+| A.3 PlantUML->RCE | Medium | None | Required | 40% |
+| B.1 REPL Social Eng | Low | None | Required | 60% |
+| C.1 Combined XSS-RCE | Low | None | Required | 70% |
+
+---
+
+## 9. Recommendations
+
+### 9.1 Immediate Actions (0-30 days)
+
+1. **CVE-MC-001**: Enable `contextIsolation: true` and `nodeIntegration: false` for main window
+2. **CVE-MC-002**: Add confirmation dialog before REPL execution with code preview
+3. **CVE-MC-005**: Remove `unsafe-inline` and `unsafe-eval` from CSP
+4. **CVE-MC-006**: Fix PDF export window security settings
+
+### 9.2 Short-term Actions (30-90 days)
+
+1. **CVE-MC-002**: Implement sandboxed code execution environment
+2. **CVE-MC-003**: Enhance DOMPurify configuration, add CSP reporting
+3. **CVE-MC-007**: Implement local PlantUML rendering option
+4. Add comprehensive security audit logging
+
+### 9.3 Long-term Actions (90+ days)
+
+1. **CVE-MC-010**: Implement dependency pinning and SCA scanning
+2. Security awareness training for users
+3. Implement secure development lifecycle (SDL)
+4. Regular penetration testing schedule
+
+---
+
+## 10. Appendix
+
+### A. Security Configuration Audit
+
+**Main Window (main.js:323-334)**
+```javascript
+// CURRENT (INSECURE)
+webPreferences: {
+  nodeIntegration: true,      // CRITICAL: Allows require() in renderer
+  contextIsolation: false,    // CRITICAL: No isolation between contexts
+  spellcheck: true
+}
+
+// RECOMMENDED
+webPreferences: {
+  nodeIntegration: false,
+  contextIsolation: true,
+  sandbox: true,
+  spellcheck: true,
+  webSecurity: true,
+  allowRunningInsecureContent: false
+}
+```
+
+**CSP Configuration (index.html:5)**
+```html
+<!-- CURRENT (WEAK) -->
+<meta http-equiv="Content-Security-Policy"
+  content="default-src 'self';
+           script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net;
+           ...">
+
+<!-- RECOMMENDED -->
+<meta http-equiv="Content-Security-Policy"
+  content="default-src 'self';
+           script-src 'self';
+           style-src 'self';
+           img-src 'self' data:;
+           connect-src 'self';
+           frame-src 'none';
+           object-src 'none'">
+```
+
+### B. IPC Channel Security Review
+
+**High-Risk Channels:**
+| Channel | Risk | Recommendation |
+|---------|------|----------------|
+| `execute-code` | Critical | Remove or sandbox |
+| `save-file` | High | Add path validation |
+| `batch-convert` | Medium | Rate limiting exists |
+| `git-*` | Medium | Audit git operations |
+
+### C. Dependency Security
+
+**Critical Dependencies:**
+| Package | Version | Known CVEs | Recommendation |
+|---------|---------|------------|----------------|
+| electron | 37.4.0 | None | Pin version |
+| dompurify | 3.3.1 | None | Keep updated |
+| marked | 17.0.3 | None | Keep updated |
+| mermaid | 11.12.3 | None | Review CSP impact |
+
+---
+
+## Document Control
+
+| Version | Date | Author | Changes |
+|---------|------|--------|---------|
+| 1.0 | 2026-03-15 | Security Team | Initial threat model |
+
+---
+
+*This threat model should be reviewed and updated after any significant architectural changes or at minimum annually.*

docs/plans/2026-03-15-react-tauri-pwa-design.md

@@ -0,0 +1,502 @@
+# MarkdownConverter v5.0 - React + Tauri + PWA Architecture Design
+
+**Date:** 2026-03-15
+**Status:** Approved
+**Target Platforms:** Desktop (Tauri), Web (PWA), Mobile (Future)
+
+---
+
+## Executive Summary
+
+This document outlines the architecture for MarkdownConverter v5.0, a complete rewrite using React, Tauri, and PWA technologies. The new architecture enables:
+
+- **Multi-platform support**: Single codebase for desktop, web, and future mobile
+- **Improved security**: Eliminates critical Electron vulnerabilities by design
+- **Reduced bundle size**: ~5-10MB desktop, ~137KB web (vs 150MB+ Electron)
+- **Better maintainability**: Component-based architecture with TypeScript
+- **Offline support**: Full PWA capabilities with IndexedDB storage
+
+---
+
+## 1. Project Structure
+
+```
+markdown-converter-v5/
+├── src/
+│   ├── components/
+│   │   ├── ui/                    # Shadcn/ui components (button, dialog, etc.)
+│   │   ├── editor/                # CodeMirror wrapper, toolbar
+│   │   ├── preview/               # Markdown preview, theme rendering
+│   │   ├── sidebar/               # Explorer, Git, Snippets, Templates panels
+│   │   ├── tabs/                  # Tab bar, tab management
+│   │   ├── dialogs/               # Export, batch converter, settings dialogs
+│   │   └── layout/                # Main layout, splitter panes
+│   │
+│   ├── hooks/
+│   │   ├── useEditor.ts           # Editor state & actions
+│   │   ├── useTheme.ts            # Theme management
+│   │   ├── useFileSystem.ts       # File operations (uses adapter)
+│   │   ├── useConversion.ts       # Conversion operations
+│   │   └── useKeyboardShortcuts.ts
+│   │
+│   ├── stores/
+│   │   ├── editorStore.ts         # Content, tabs, cursor position
+│   │   ├── settingsStore.ts       # User preferences
+│   │   ├── themeStore.ts          # Active theme, custom themes
+│   │   └── sidebarStore.ts        # Sidebar state, active panel
+│   │
+│   ├── adapters/
+│   │   ├── types.ts               # Interface definitions
+│   │   ├── tauri/
+│   │   │   ├── index.ts           # Tauri adapter implementation
+│   │   │   ├── fs.ts              # File system via Tauri
+│   │   │   ├── convert.ts         # Pandoc, FFmpeg via Tauri
+│   │   │   └── system.ts          # System info, paths
+│   │   ├── web/
+│   │   │   ├── index.ts           # Web adapter implementation
+│   │   │   ├── fs.ts              # IndexedDB + File System Access API
+│   │   │   ├── convert.ts         # WASM converters, cloud fallback
+│   │   │   └── system.ts          # Browser capabilities
+│   │   └── index.ts               # Platform detection & export
+│   │
+│   ├── wasm/
+│   │   ├── pdf.wasm               # PDF generation
+│   │   ├── marked.wasm            # Markdown parsing (if available)
+│   │   └── loader.ts              # WASM module loader
+│   │
+│   ├── lib/
+│   │   ├── markdown.ts            # Marked + plugins config
+│   │   ├── syntax.ts              # Highlight.js config
+│   │   ├── mermaid.ts             # Diagram rendering
+│   │   └── utils.ts               # Helper functions
+│   │
+│   ├── styles/
+│   │   ├── globals.css            # Tailwind imports, CSS variables
+│   │   ├── themes/                # Theme CSS files
+│   │   └── editor.css             # CodeMirror styling
+│   │
+│   ├── types/
+│   │   ├── editor.ts              # Editor-related types
+│   │   ├── conversion.ts          # Conversion options types
+│   │   └── platform.ts            # Platform capability types
+│   │
+│   ├── App.tsx                    # Root component
+│   ├── main.tsx                   # Entry point
+│   └── vite-env.d.ts
+│
+├── src-tauri/                     # Tauri backend (Rust)
+│   ├── src/
+│   │   ├── main.rs                # Tauri entry
+│   │   ├── commands/              # IPC command handlers
+│   │   │   ├── fs.rs              # File system operations
+│   │   │   ├── convert.rs         # Pandoc, FFmpeg wrappers
+│   │   │   └── system.rs          # System utilities
+│   │   └── lib.rs
+│   ├── Cargo.toml
+│   └── tauri.conf.json
+│
+├── public/
+│   ├── manifest.json              # PWA manifest
+│   ├── sw.js                      # Service worker
+│   ├── fonts/                     # JetBrains Mono, Inter
+│   └── icons/                     # App icons
+│
+├── package.json
+├── vite.config.ts
+├── tailwind.config.ts
+├── tsconfig.json
+└── components.json                # Shadcn/ui config
+```
+
+---
+
+## 2. Component Architecture
+
+```tsx
+// Component hierarchy
+
+<App>                              // Root layout, theme provider
+├── <Layout>
+│   ├── <TitleBar />              // Draggable title bar (desktop only)
+│   ├── <TabBar />                // Document tabs
+│   ├── <MainContent>
+│   │   ├── <Sidebar>             // Collapsible sidebar
+│   │   │   ├── <ExplorerPanel />
+│   │   │   ├── <GitPanel />
+│   │   │   ├── <SnippetsPanel />
+│   │   │   └── <TemplatesPanel />
+│   │   ├── <EditorPane>          // Split view container
+│   │   │   ├── <CodeMirrorEditor />
+│   │   │   └── <PreviewPane>
+│   │   │       └── <MarkdownPreview />
+│   │   └── <BottomPanel>         // REPL, terminal, output
+│   └── <StatusBar />             // Line count, encoding, status
+│
+└── <Dialogs>                      // Portal-based dialogs
+    ├── <ExportDialog />
+    ├── <BatchConvertDialog />
+    ├── <SettingsDialog />
+    ├── <ThemeDialog />
+    └── <PdfEditorDialog />
+```
+
+**Key Components:**
+
+| Component | Props | Responsibility |
+|-----------|-------|----------------|
+| `CodeMirrorEditor` | `content`, `onChange`, `theme` | Wrap CodeMirror 6 with React |
+| `MarkdownPreview` | `content`, `theme` | Render sanitized HTML with themes |
+| `TabBar` | `tabs`, `activeId`, `onSelect`, `onClose` | Manage document tabs |
+| `Sidebar` | `activePanel`, `collapsed` | Collapsible sidebar container |
+| `ExportDialog` | `format`, `options` | Export configuration UI |
+
+---
+
+## 3. State Management (Zustand)
+
+### Editor Store
+
+```typescript
+interface Tab {
+  id: string;
+  title: string;
+  content: string;
+  filePath?: string;
+  isDirty: boolean;
+  cursorPosition: { line: number; column: number };
+}
+
+interface EditorState {
+  tabs: Tab[];
+  activeTabId: string | null;
+
+  // Actions
+  createTab: (title?: string) => string;
+  closeTab: (id: string) => void;
+  setActiveTab: (id: string) => void;
+  updateContent: (id: string, content: string) => void;
+  updateCursorPosition: (id: string, pos: { line: number; column: number }) => void;
+  markSaved: (id: string, filePath?: string) => void;
+}
+```
+
+### Settings Store
+
+```typescript
+interface SettingsState {
+  theme: string;
+  fontSize: number;
+  fontFamily: string;
+  previewMode: 'split' | 'editor' | 'preview';
+  showLineNumbers: boolean;
+  wordWrap: boolean;
+  autoSave: boolean;
+  autoSaveInterval: number;
+}
+```
+
+**Stores Summary:**
+
+| Store | State | Persisted |
+|-------|-------|-----------|
+| `editorStore` | Tabs, content, cursor | Tab metadata only |
+| `settingsStore` | User preferences | Yes |
+| `themeStore` | Active theme, custom themes | Yes |
+| `sidebarStore` | Panel state, width | Yes |
+
+---
+
+## 4. Platform Adapters
+
+### Adapter Interface
+
+```typescript
+export interface PlatformAdapter {
+  name: 'tauri' | 'web';
+
+  // File System
+  fs: {
+    readFile: (path: string) => Promise<string>;
+    writeFile: (path: string, content: string) => Promise<void>;
+    deleteFile: (path: string) => Promise<void>;
+    listDirectory: (path: string) => Promise<FileInfo[]>;
+    exists: (path: string) => Promise<boolean>;
+    watchDirectory?: (path: string, callback: WatchCallback) => () => void;
+  };
+
+  // Conversion
+  convert: {
+    toPdf: (content: string, options: PdfOptions) => Promise<Blob>;
+    toDocx: (content: string, options: DocxOptions) => Promise<Blob>;
+    toHtml: (content: string, options: HtmlOptions) => Promise<string>;
+    batchConvert: (files: string[], format: string) => Promise<ConversionResult[]>;
+  };
+
+  // Capabilities
+  capabilities: {
+    hasPandoc: boolean;
+    hasFfmpeg: boolean;
+    hasLibreOffice: boolean;
+    hasDirectFs: boolean;
+    hasSystemNotifications: boolean;
+  };
+}
+```
+
+### Platform Detection
+
+```typescript
+// Auto-detect platform at startup
+const isTauri = typeof window !== 'undefined' &&
+                '__TAURI__' in window;
+
+export const adapter: PlatformAdapter = isTauri
+  ? tauriAdapter
+  : webAdapter;
+```
+
+### Capability Differences
+
+| Feature | Tauri (Desktop) | Web (PWA) |
+|---------|-----------------|-----------|
+| File System | Direct access | IndexedDB + File System Access API |
+| PDF Export | Pandoc (native) | WASM converter |
+| DOCX Export | Pandoc (native) | Limited/not available |
+| Media Conversion | FFmpeg (native) | Cloud API or limited |
+| File Watching | Native events | Not available |
+| Offline | Always | Service Worker |
+
+---
+
+## 5. Build Configuration
+
+### Vite Configuration
+
+- Target: ESNext
+- Minifier: esbuild
+- Code splitting by vendor chunks
+- Source maps enabled
+
+### Tailwind Configuration
+
+- Dark mode: `class` strategy
+- Custom colors using CSS variables
+- Custom font families (JetBrains Mono, Inter)
+- Tailwindcss-animate plugin
+
+### TypeScript Configuration
+
+- Target: ES2022
+- Strict mode enabled
+- All strict checks enabled
+- Path aliases (`@/*`)
+
+### Bundle Sizes (Estimated)
+
+| Chunk | Size (gzipped) |
+|-------|----------------|
+| `vendor-react` | ~12KB |
+| `vendor-editor` | ~45KB |
+| `vendor-markdown` | ~35KB |
+| `vendor-ui` | ~15KB |
+| `app` (your code) | ~30KB |
+| **Total PWA** | **~137KB** |
+| Tauri desktop | ~5-10MB (with WebView) |
+
+---
+
+## 6. Tauri Backend (Rust)
+
+### IPC Commands
+
+**File System:**
+- `read_file` - Read file content
+- `write_file` - Write file content
+- `delete_file` - Delete file
+- `list_directory` - List directory contents
+- `path_exists` - Check path existence
+- `watch_directory` - Watch for file changes
+
+**Conversion:**
+- `to_pdf` - Convert to PDF via Pandoc
+- `to_docx` - Convert to DOCX via Pandoc
+- `to_html` - Convert to HTML via Pandoc
+- `batch_convert` - Batch conversion
+
+**System:**
+- `check_dependencies` - Check for Pandoc, FFmpeg, LibreOffice
+- `get_config_dir` - Get config directory path
+
+### Security Comparison
+
+| Aspect | Electron (Current) | Tauri |
+|--------|-------------------|-------|
+| `nodeIntegration` | `true` (CVE) | Not possible |
+| `contextIsolation` | `false` (CVE) | Always enforced |
+| Bundle size | ~150MB | ~5-10MB |
+| Memory usage | Higher | Lower |
+| IPC security | Manual whitelist | Compile-time verified |
+
+---
+
+## 7. PWA Configuration
+
+### Web App Manifest
+
+- Name: Markdown Converter
+- Display: Standalone
+- Theme color: #5661b3
+- File handlers for .md, .markdown, .txt
+- Share target for receiving shared content
+
+### Service Worker
+
+- Cache-first for static assets
+- Network-first for API calls
+- Stale-while-revalidate for dynamic content
+- Automatic update detection
+
+### IndexedDB Storage
+
+**Stores:**
+- `files` - Offline file storage
+- `settings` - User preferences
+- `templates` - Custom templates
+
+### PWA Features
+
+| Feature | Implementation |
+|---------|---------------|
+| Offline support | Service Worker + IndexedDB |
+| Install prompt | Web App Manifest |
+| File handling | File System Access API (Chrome) |
+| Share target | Share Target API |
+| Background sync | Background Sync API |
+
+---
+
+## 8. Migration Plan
+
+### Timeline: 8 Weeks
+
+**Phase 1: Foundation (Week 1-2)**
+- Initialize new repo
+- Setup Vite + React + TypeScript
+- Configure Tailwind + Shadcn/ui
+- Setup Zustand stores
+- Create platform adapter interfaces
+- Setup Tauri project structure
+
+**Phase 2: Core Editor (Week 3-4)**
+- CodeMirrorEditor component
+- MarkdownPreview component
+- SplitPane layout
+- Theme system
+- Tab management
+- Keyboard shortcuts
+
+**Phase 3: Sidebar & Panels (Week 5)**
+- Sidebar container
+- ExplorerPanel
+- GitPanel
+- SnippetsPanel
+- TemplatesPanel
+- Bottom panel
+
+**Phase 4: Platform Adapters (Week 6)**
+- Web adapter implementation
+- Tauri adapter implementation
+- File system operations
+- PDF conversion
+- Capability detection
+
+**Phase 5: Export & Conversion (Week 7)**
+- ExportDialog
+- BatchConvertDialog
+- UniversalConverterDialog
+- ImageConverterDialog
+- AudioConverterDialog
+- VideoConverterDialog
+- PDF Editor Dialog
+
+**Phase 6: PWA & Polish (Week 8)**
+- Service Worker setup
+- Web App Manifest
+- IndexedDB storage
+- Offline mode indicator
+- Settings persistence
+- Accessibility audit
+- Performance optimization
+
+### Parallel Development Strategy
+
+```
+Current Electron App (v4.x)     New React+Tauri App (v5.0)
+        │                               │
+        │  Bug fixes only               │  Active development
+        │  Security patches             │  Feature migration
+        ▼                               ▼
+   Stable release  ────────────>  Beta release
+   (maintained)                    (new features)
+```
+
+---
+
+## 9. Design Decisions Summary
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| Code Structure | Single repo with platform adapters | Lightest weight, clean separation |
+| State Management | Zustand | Minimal (~1KB), simple API |
+| UI Library | Shadcn/ui + Tailwind | Copy-paste ownership, excellent DX |
+| Build Tool | Vite | Industry standard, fast HMR |
+| TypeScript | Strict mode | Maximum type safety |
+| Desktop Features | Hybrid (WASM core, desktop advanced) | Best of both worlds |
+| Migration | Parallel development | Zero disruption to stable release |
+
+---
+
+## 10. Success Criteria
+
+- [ ] All core editor features functional on both Tauri and PWA
+- [ ] Bundle size under 150KB for PWA
+- [ ] All 13 themes migrated and working
+- [ ] Export to PDF works on both platforms
+- [ ] Offline mode fully functional in PWA
+- [ ] WCAG 2.1 AA accessibility compliance
+- [ ] TypeScript strict mode with no `any` types
+- [ ] All IPC channels have TypeScript types
+- [ ] Security audit passes with no critical issues
+
+---
+
+## Appendix: Dependencies
+
+### Production Dependencies
+
+- `react` - UI library
+- `react-dom` - React DOM renderer
+- `zustand` - State management
+- `@radix-ui/react-*` - Headless UI primitives
+- `@codemirror/*` - Code editor
+- `marked` - Markdown parser
+- `highlight.js` - Syntax highlighting
+- `mermaid` - Diagram rendering
+- `dompurify` - HTML sanitization
+- `class-variance-authority` - Component variants
+- `clsx` + `tailwind-merge` - Class utilities
+- `lucide-react` - Icons
+
+### Development Dependencies
+
+- `@tauri-apps/cli` - Tauri CLI
+- `typescript` - TypeScript compiler
+- `vite` - Build tool
+- `tailwindcss` - CSS framework
+- `eslint` - Linting
+- `prettier` - Formatting
+
+---
+
+*Document generated: 2026-03-15*
+*Next step: Invoke writing-plans skill to create detailed implementation plan*

docs/plans/2026-03-24-modal-system-design.md

@@ -0,0 +1,202 @@
+# Modal System Design
+
+**Date:** 2026-03-24
+**Version:** 4.0.0
+**Status:** Approved
+
+## Overview
+
+Replace the existing dialog implementations with a unified modal system that provides:
+- Glassmorphism backdrop matching app aesthetic
+- Full accessibility (ARIA, focus trap, keyboard navigation)
+- Smooth fade + scale animations
+- Consistent API via `ModalManager` class
+
+## Decisions Made
+
+| Decision | Choice | Rationale |
+|----------|--------|-----------|
+| Architecture | Unified `ModalManager` class | Cleaner, consistent behavior across all modals |
+| Backdrop style | Glassmorphism | Matches existing app design language |
+| Focus management | Focus first interactive element | Standard, predictable behavior |
+| Animation | Fade + scale (95% → 100%) | Modern, subtle effect |
+| Implementation | Custom (not native `<dialog>`) | Full control, no polyfill concerns |
+
+## Architecture
+
+### File Structure
+
+```
+src/
+├── utils/
+│   └── ModalManager.js    # Core modal logic (~150 lines)
+├── styles/
+│   └── modal.css          # Unified modal styles (~200 lines)
+└── index.html             # Updated dialog markup
+```
+
+### ModalManager Class
+
+```javascript
+class ModalManager {
+  constructor(element, options = {})
+  open()                    // Show modal with animation
+  close()                   // Hide modal with animation
+  destroy()                 // Cleanup event listeners
+  on(event, callback)       // Event subscription
+
+  // Internal
+  #createBackdrop()         // Create glassmorphism backdrop
+  #trapFocus()              // Manage focus within modal
+  #handleKeydown(e)         // Escape key handler
+  #getFocusableElements()   // Query focusable children
+}
+```
+
+### Events
+
+- `open` — Fired after open animation completes
+- `close` — Fired after close animation completes
+
+## CSS Design
+
+### Variables (from tokens.css)
+
+```css
+--z-modal: 200;
+--transition-normal: 200ms cubic-bezier(0.4, 0, 0.2, 1);
+--shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);
+--radius-lg: 0.5rem;
+```
+
+### Backdrop
+
+```css
+.modal-backdrop {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.4);
+  backdrop-filter: blur(4px);
+  -webkit-backdrop-filter: blur(4px);
+  z-index: var(--z-modal);
+}
+```
+
+### Modal Container
+
+```css
+.modal {
+  position: fixed;
+  inset: 0;
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: calc(var(--z-modal) + 1);
+  opacity: 0;
+  visibility: hidden;
+  transition: opacity var(--transition-normal),
+              visibility var(--transition-normal);
+}
+
+.modal.open {
+  opacity: 1;
+  visibility: visible;
+}
+```
+
+### Modal Content (with animation)
+
+```css
+.modal-content {
+  background: hsl(var(--background));
+  border-radius: var(--radius-lg);
+  box-shadow: var(--shadow-xl);
+  max-width: 90vw;
+  max-height: 90vh;
+  overflow: hidden;
+  transform: scale(0.95);
+  transition: transform var(--transition-normal);
+}
+
+.modal.open .modal-content {
+  transform: scale(1);
+}
+```
+
+## HTML Structure
+
+All dialogs convert to unified structure:
+
+```html
+<div id="export-dialog"
+     class="modal"
+     role="dialog"
+     aria-modal="true"
+     aria-labelledby="export-dialog-title">
+
+  <div class="modal-backdrop" data-close></div>
+
+  <div class="modal-content">
+    <div class="modal-header">
+      <h3 id="export-dialog-title">Export Options</h3>
+      <button class="modal-close" aria-label="Close">&times;</button>
+    </div>
+
+    <div class="modal-body">
+      <!-- Dialog-specific content -->
+    </div>
+
+    <div class="modal-footer">
+      <button class="btn btn-secondary" data-close>Cancel</button>
+      <button class="btn btn-primary">Confirm</button>
+    </div>
+  </div>
+</div>
+```
+
+### Key Attributes
+
+- `role="dialog"` — Screen reader identification
+- `aria-modal="true"` — Prevents screen reader from accessing background
+- `aria-labelledby` — References the dialog title
+- `data-close` — Click handler for closing (backdrop, cancel buttons)
+
+## Accessibility Features
+
+1. **Focus trap** — Tab cycles within modal only
+2. **Focus first element** — Auto-focuses first input/button on open
+3. **Escape key** — Closes modal
+4. **Click outside** — Clicking backdrop closes modal
+5. **Focus restoration** — Returns focus to trigger element on close
+6. **ARIA attributes** — Proper screen reader support
+
+## Dialogs to Migrate
+
+| Dialog ID | Current Class | Complexity |
+|-----------|--------------|------------|
+| `find-dialog` | `.find-dialog` | Simple |
+| `export-dialog` | `.export-dialog` | Complex (many sections) |
+| `print-preview-overlay` | `.export-dialog` | Medium |
+| `table-generator-dialog` | `.export-dialog` | Simple |
+| `ascii-art-dialog` | `.export-dialog` | Medium |
+| `universal-converter-dialog` | `.export-dialog` | Complex |
+| `batch-dialog` | `.batch-dialog` | Complex |
+| `pdf-editor-dialog` | `.export-dialog` | Complex |
+| `header-footer-dialog` | `.export-dialog` | Medium |
+| `field-picker-dialog` | `.export-dialog` | Simple |
+
+## Migration Steps
+
+1. Create `src/utils/ModalManager.js`
+2. Create `src/styles/modal.css`
+3. Update `index.html` to include new stylesheet
+4. Convert each dialog HTML to new structure
+5. Initialize `ModalManager` instances in `renderer.js`
+6. Remove old CSS from `styles.css`
+7. Test all dialogs
+
+## Out of Scope
+
+- Modal nesting (stacked modals) — can be added later if needed
+- Animated backdrop (currently static blur)
+- Modal size variants (small/large/fullscreen) — can use inline styles

docs/plans/2026-03-24-v4-enhancement-flutter-design.md

@@ -0,0 +1,326 @@
+# V4 Enhancement + Flutter Exploration Design
+
+**Date:** 2026-03-24
+**Status:** Approved
+**Approach:** Incremental V4 Enhancement + Flutter Spike (70/30 split)
+
+---
+
+## Executive Summary
+
+This design outlines a two-track approach:
+1. **V4 Enhancement (70%)**: Fix critical bugs, optimize performance, add platform adapters, improve UI patterns
+2. **Flutter Exploration (30%)**: Build proof-of-concept for cross-platform evaluation (Windows, Mobile, Web)
+
+---
+
+## Goals & Scope
+
+### Primary Goals
+1. **Fix critical bug**: PDF and markdown multitab functionality
+2. **Performance improvements**: Faster startup, smoother editing, responsive preview
+3. **Architecture improvements**: Platform adapters, cleaner state management
+4. **Flutter research**: Proof-of-concept for cross-platform evaluation
+
+### Out of Scope
+- Full V5 migration
+- Complete UI redesign
+- New features (focus on optimization)
+
+### Success Criteria
+
+| Metric | Current | Target |
+|--------|---------|--------|
+| Startup time | ~3-5s | <2s |
+| Editor typing latency | Noticeable lag | <16ms |
+| Preview render (1MB file) | ~500ms | <200ms |
+| Memory usage | ~300MB | <200MB |
+| Bundle size | ~150MB | <100MB |
+
+---
+
+## Section 1: V4 Critical Fixes & Performance Optimizations
+
+### 1.1 Fix: PDF/Markdown Multitab Bug
+
+**Location:** `src/renderer.js` (TabManager class)
+
+**Investigation areas:**
+- `switchToTab()` - ensure proper state preservation
+- `closeTab()` - ensure EditorView cleanup
+- Add tab type tracking (markdown vs pdf)
+- Isolate PDF viewer state from editor state
+
+### 1.2 Startup Performance Optimizations
+
+| Optimization | Implementation | Expected Gain |
+|--------------|----------------|---------------|
+| Defer Mermaid | Load only when diagram detected | ~500ms |
+| Defer PDF.js | Load on first PDF open | ~800ms |
+| Lazy load themes | Load active theme only | ~200ms |
+| Lazy sidebar panels | Load panel code when sidebar opens | ~300ms |
+| Preload optimization | Remove unused IPC channels | ~100ms |
+
+**Lazy loading pattern:**
+```javascript
+// Current (loads everything upfront)
+const { dialog } = require('@electron/remote');
+
+// Optimized (load on demand)
+let _dialog;
+function getDialog() {
+  if (!_dialog) _dialog = require('@electron/remote').dialog;
+  return _dialog;
+}
+```
+
+### 1.3 Editor Performance
+
+| Issue | Solution |
+|-------|----------|
+| Typing lag with large files | Debounce preview updates (300ms) |
+| Syntax highlight overhead | Use highlight.js lazy mode |
+| Memory leaks | Clean up EditorView on tab close |
+| Theme switching lag | Pre-compile theme CSS |
+
+### 1.4 Preview Rendering
+
+| Issue | Solution |
+|-------|----------|
+| Mermaid slow | Render on-demand, cache results |
+| Full re-render on keystroke | Debounced incremental updates |
+| Large documents | Viewport rendering (visible portion only) |
+
+---
+
+## Section 2: Platform Adapter Pattern
+
+### 2.1 Architecture
+
+```
+src/
+├── adapters/
+│   ├── index.js              # Auto-detects and exports adapter
+│   ├── types.js              # Interface definitions (JSDoc)
+│   │
+│   ├── electron/             # Current Electron implementation
+│   │   ├── index.js          # Exports electronAdapter
+│   │   ├── fs.js             # File system operations
+│   │   ├── convert.js        # Pandoc, FFmpeg conversions
+│   │   ├── pdf.js            # PDF operations
+│   │   └── system.js         # System info, dialogs, notifications
+│   │
+│   └── mock/                 # For testing
+│       └── index.js          # Mock adapter for unit tests
+```
+
+### 2.2 Adapter Interface
+
+```javascript
+/**
+ * @typedef {Object} PlatformAdapter
+ * @property {'electron'} name
+ * @property {FileSystemAdapter} fs
+ * @property {ConversionAdapter} convert
+ * @property {PdfAdapter} pdf
+ * @property {SystemAdapter} system
+ */
+
+/**
+ * @typedef {Object} FileSystemAdapter
+ * @property {(path: string) => Promise<string>} readFile
+ * @property {(path: string, content: string) => Promise<void>} writeFile
+ * @property {(path: string) => Promise<void>} deleteFile
+ * @property {(path: string) => Promise<FileInfo[]>} listDirectory
+ * @property {(path: string) => Promise<boolean>} exists
+ */
+```
+
+### 2.3 Migration Strategy
+
+| Phase | What | Files Affected |
+|-------|------|----------------|
+| 1 | Create adapter structure | New files only |
+| 2 | Migrate file operations | `renderer.js`, `sidebar/*.js` |
+| 3 | Migrate conversions | Export dialogs |
+| 4 | Migrate PDF operations | PDF viewer |
+| 5 | Remove old IPC calls | `preload.js` cleanup |
+
+---
+
+## Section 3: UI Improvements (Shadcn/ui Patterns)
+
+### 3.1 Design Token System
+
+```css
+/* src/styles/tokens.css */
+
+:root {
+  /* Colors - Light mode */
+  --background: 0 0% 100%;
+  --foreground: 222.2 84% 4.9%;
+  --primary: 227 44% 52%;
+  --primary-foreground: 210 40% 98%;
+  --secondary: 210 40% 96.1%;
+  --secondary-foreground: 222.2 47.4% 11.2%;
+  --muted: 210 40% 96.1%;
+  --muted-foreground: 215.4 16.3% 46.9%;
+  --destructive: 0 84.2% 60.2%;
+  --border: 214.3 31.8% 91.4%;
+  --ring: 227 44% 52%;
+
+  /* Spacing & Radii */
+  --radius: 0.5rem;
+}
+```
+
+### 3.2 Component Improvements
+
+| Component | Current Issue | Fix |
+|-----------|---------------|-----|
+| Buttons | Inconsistent hover/focus | Use `.btn` with variants |
+| Dialogs | Missing focus trap | Add focus trap, Escape key, aria-modal |
+| Tabs | No keyboard navigation | Add arrow key nav, aria-selected |
+| Sidebar | No collapse animation | CSS transitions |
+| Dropdowns | Missing click-outside | Add proper event handling |
+
+### 3.3 Accessibility Improvements
+
+- Focus states with `:focus-visible`
+- Skip to content link
+- ARIA labels on interactive elements
+- Keyboard navigation for all components
+
+---
+
+## Section 4: Flutter Exploration (30% Effort)
+
+### 4.1 Flutter Project Structure
+
+```
+markdown-converter-flutter/
+├── lib/
+│   ├── main.dart
+│   ├── app.dart
+│   ├── core/
+│   │   ├── theme/
+│   │   └── constants.dart
+│   ├── features/
+│   │   ├── editor/
+│   │   ├── preview/
+│   │   └── tabs/
+│   ├── services/
+│   │   ├── file_service.dart
+│   │   ├── export_service.dart
+│   │   └── platform_service.dart
+│   └── adapters/
+│       ├── file_adapter.dart
+│       ├── file_adapter_mobile.dart
+│       ├── file_adapter_web.dart
+│       └── file_adapter_desktop.dart
+├── pubspec.yaml
+├── windows/
+├── web/
+└── lib/
+```
+
+### 4.2 Key Dependencies
+
+```yaml
+dependencies:
+  flutter_markdown: ^0.7.0
+  flutter_code_editor: ^0.3.0
+  provider: ^6.1.0
+  file_picker: ^8.0.0
+  path_provider: ^2.1.0
+  pdf: ^3.10.0
+  printing: ^5.12.0
+```
+
+### 4.3 Prototype Features
+
+| Feature | Priority |
+|---------|----------|
+| Basic markdown editor | Must have |
+| Live preview | Must have |
+| Light/dark theme | Must have |
+| Tab management | Should have |
+| File open/save | Should have |
+| PDF export | Nice to have |
+| Windows exe build | Must have |
+| Web build | Must have |
+| Mobile build | Should have |
+
+### 4.4 Evaluation Criteria
+
+| Metric | Target |
+|--------|--------|
+| Windows exe size | <50MB |
+| Web initial load | <500KB |
+| Cold start time | <2s |
+| Editor typing latency | <16ms |
+
+### 4.5 Flutter vs Tauri Comparison
+
+| Aspect | Flutter | Tauri + React |
+|--------|---------|---------------|
+| Mobile support | ✅ Excellent | ❌ Requires separate app |
+| Web performance | ⚠️ Good, larger | ✅ Excellent, small |
+| Desktop bundle | ⚠️ ~30-50MB | ✅ ~5-10MB |
+| Native feel | ⚠️ Custom rendering | ✅ System WebView |
+| Code reuse | ✅ 100% shared | ⚠️ Some platform-specific |
+
+---
+
+## Implementation Timeline
+
+### Phase 1: V4 Critical Fixes (Week 1)
+- Fix PDF/markdown multitab bug
+- Implement startup optimizations
+- Add debounced preview rendering
+
+### Phase 2: Platform Adapters (Week 2)
+- Create adapter structure
+- Migrate file operations
+- Migrate conversions
+
+### Phase 3: UI Improvements (Week 3)
+- Add design tokens
+- Improve component accessibility
+- Add keyboard navigation
+
+### Phase 4: Flutter Prototype (Weeks 2-4, parallel)
+- Set up Flutter project
+- Implement basic editor
+- Build Windows and Web versions
+- Document findings
+
+---
+
+## Risk Mitigation
+
+| Risk | Mitigation |
+|------|------------|
+| Multitab fix causes regressions | Comprehensive test suite before changes |
+| Performance optimizations break features | Incremental changes with benchmarks |
+| Flutter proves unsuitable | 30% effort limit, V4 remains primary |
+| Platform adapter migration too slow | Phased approach, each phase independent |
+
+---
+
+## Success Metrics
+
+- [ ] Multitab functionality working correctly
+- [ ] Startup time < 2 seconds
+- [ ] No perceived editor lag with files < 1MB
+- [ ] Preview renders in < 200ms
+- [ ] Bundle size reduced by 30%+
+- [ ] Platform adapters for fs, convert, pdf implemented
+- [ ] Design tokens applied to all components
+- [ ] Flutter prototype running on Windows + Web
+- [ ] Flutter evaluation documented with recommendation
+
+---
+
+*Document generated: 2026-03-24*
+*Next step: Create detailed implementation plan*

docs/plans/2026-04-06-writers-studio-design.md

@@ -0,0 +1,335 @@
+# Writer's Studio Feature Pack — Design Document
+
+**Date**: 2026-04-06
+**Version**: 4.2.0 target
+**Status**: Approved
+**Scope**: Three cohesive features to transform MarkdownConverter into a writing environment
+
+---
+
+## Overview
+
+The Writer's Studio Feature Pack adds three interconnected features to MarkdownConverter:
+
+1. **Zen Mode** — Distraction-free writing environment with typewriter scrolling
+2. **Document Outline** — Heading hierarchy sidebar panel for navigation
+3. **Writing Analytics** — Real-time readability and vocabulary analysis dashboard
+
+These features work together: Zen Mode creates the environment, Outline provides navigation, Analytics gives insight.
+
+---
+
+## Feature 1: Zen Mode
+
+### Purpose
+
+Transform the app from a multi-tool into a focused writing environment. Inspired by iA Writer, Typora, and Bear.
+
+### New Files
+
+- `src/zen-mode.js` — ZenMode class (~150 lines)
+- `src/styles-zen.css` — Zen mode specific styles (~120 lines)
+
+### Integration Points
+
+- `src/renderer.js` — Initialize ZenMode, register F11 shortcut, add View > Zen Mode menu
+- `src/editor/codemirror-setup.js` — Export typewriter + dimming extensions
+
+### Behavior
+
+**Toggle**: F11, View > Zen Mode, command palette "Toggle Zen Mode"
+**Exit**: Escape key, F11 again
+
+**What hides**:
+- Tab bar
+- Toolbar
+- Sidebar (collapsed)
+- Status bar
+- App header
+
+**What shows**:
+- Editor (full viewport)
+- Floating HUD (bottom-center, semi-transparent)
+
+### Floating HUD
+
+```
+┌─────────────────────────────────────────┐
+│  847 words  •  ~4 min  •  23:45 session │
+│  ████████████████░░░░  85% of 1000      │
+└─────────────────────────────────────────┘
+```
+
+- Word count (from existing status bar logic)
+- Estimated reading time (~200 wpm)
+- Session timer (starts when zen mode activates)
+- Optional progress bar toward word goal
+
+### CodeMirror Extensions
+
+**Typewriter Scroll** (`ViewPlugin`):
+- Listens to `EditorView.update` for selection changes
+- Calls `editor.dispatch({ effects: EditorView.scrollIntoView(pos, { y: 'center' }) })`
+- Smooth scrolling with `scrollBehavior: 'smooth'` in CSS
+
+**Line Dimming** (`ViewPlugin` + `Decoration`):
+- Builds a `DecorationSet` mapping each line to an opacity value
+- Active line: opacity 1.0
+- 1-2 lines away: 0.7
+- 3-4 lines away: 0.5
+- 5+ lines away: 0.3
+- Uses `Decoration.line({ attributes: { style: 'opacity: X' } })`
+
+### Centered Column
+
+CSS applied to `.zen-mode .cm-content`:
+```css
+.zen-mode .cm-content {
+    max-width: 700px;
+    margin: 0 auto;
+    font-size: 18px;
+    line-height: 1.8;
+}
+```
+
+### State Management
+
+- `this.previousState` stores which UI elements were visible before zen mode
+- On exit, restores all elements to their previous visibility
+- Editor content, cursor position, and scroll state are never modified
+
+---
+
+## Feature 2: Document Outline Panel
+
+### Purpose
+
+Provide always-visible heading navigation for documents of any length. The single most-requested navigation feature for multi-section documents.
+
+### New Files
+
+- `src/sidebar/outline-panel.js` — `renderOutlinePanel` function (~100 lines)
+
+### Modified Files
+
+- `src/index.html` — Add outline icon button in sidebar icons strip
+- `src/renderer.js` — Register 'outline' panel, provide editor reference
+
+### Sidebar Integration
+
+Uses existing `SidebarManager.registerPanel()` API:
+```javascript
+sidebarManager.registerPanel('outline', {
+    title: 'Outline',
+    render: (container) => renderOutlinePanel(container, editor, editorContent)
+});
+```
+
+New icon button in sidebar strip (after templates icon):
+```html
+<button class="sidebar-icon" data-panel="outline" title="Outline (Ctrl+Shift+O)">
+    <!-- hierarchy/list icon SVG -->
+</button>
+```
+
+### Parsing Logic
+
+Parse headings from raw markdown content using regex:
+```javascript
+const headingRegex = /^(#{1,6})\s+(.+)$/gm;
+```
+
+Returns array of:
+```javascript
+{ level: 1-6, text: "Heading Text", line: 42 }
+```
+
+Debounced at 300ms to avoid re-parsing on every keystroke.
+
+### UI Structure
+
+```
+┌──────────────────────────────────────────┐
+│  OUTLINE                          ☰      │
+├──────────────────────────────────────────┤
+│  ▸ Introduction                  (H1)    │
+│    ▸ Getting Started             (H2)    │
+│    ▸ Prerequisites               (H2)    │
+│      ▸ Node.js                   (H3) ◄  │
+│    ▸ Installation                (H2)    │
+│  ▸ Features                      (H1)    │
+│    ▸ Editor                      (H2)    │
+│    ▸ Export                      (H2)    │
+├──────────────────────────────────────────┤
+│  9 headings  •  2 H1  •  4 H2  •  3 H3  │
+└──────────────────────────────────────────┘
+```
+
+- Indentation based on heading level (H1 = 0px, H2 = 16px, H3 = 32px, etc.)
+- Current heading highlighted with accent color (◄ indicator)
+- Hover shows full heading text if truncated
+
+### Click-to-Navigate
+
+```javascript
+editor.dispatch({
+    effects: EditorView.scrollIntoView(linePos, { y: 'center' })
+});
+```
+
+Brief highlight animation on the target line (fades out over 500ms).
+
+### Current Heading Sync
+
+On editor update (debounced 100ms):
+1. Get cursor line number
+2. Find the last heading whose line number <= cursor line
+3. Set that heading as active in the outline
+
+### Empty State
+
+When no headings found:
+```
+No headings found
+
+Use # to create headings:
+# Heading 1
+## Heading 2
+### Heading 3
+```
+
+---
+
+## Feature 3: Writing Analytics
+
+### Purpose
+
+Give writers real-time insight into their document's readability, structure, and vocabulary. This is the "surprise" feature most Markdown editors lack.
+
+### New Files
+
+- `src/analytics/writing-analytics.js` — `WritingAnalytics` class (~180 lines)
+- `src/analytics/analytics-panel.js` — `renderAnalyticsPanel` function (~120 lines)
+
+### Integration Points
+
+- `src/renderer.js` — Register Ctrl+Shift+A shortcut, command palette entry, View menu item
+
+### Trigger
+
+- Keyboard: `Ctrl+Shift+A`
+- Command Palette: "Show Writing Analytics"
+- Menu: View > Writing Analytics
+
+### Presentation
+
+Uses existing `ModalManager` to show a modal overlay with analytics dashboard.
+
+```
+┌─────────────────────────────────────────────────────┐
+│  Writing Analytics                              ✕   │
+├─────────────────────────────────────────────────────┤
+│                                                      │
+│  ┌─ Readability ──────────────────────────────────┐ │
+│  │  Flesch Reading Ease:  67.3 (Standard)    ○   │ │
+│  │  Grade Level:          8.2              ○○○●○  │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Timing ───────────────────────────────────────┐ │
+│  │  Reading Time:   ~4 min                        │ │
+│  │  Speaking Time:  ~6 min                        │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Structure ────────────────────────────────────┐ │
+│  │  Sentences:  42  •  Paragraphs:  8            │ │
+│  │  Avg Sentence:  14.2 words                     │ │
+│  │  Longest:  38 words ("The quick brown fox...") │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Vocabulary ───────────────────────────────────┐ │
+│  │  Unique: 312 / 847 words (36.8%)               │ │
+│  │  Top: the(42) and(31) markdown(28) ...         │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+│  ┌─ Word Goal ────────────────────────────────────┐ │
+│  │  Target: [1000] words                          │ │
+│  │  ████████████████░░░░  847/1000 (85%)          │ │
+│  └─────────────────────────────────────────────────┘ │
+│                                                      │
+└─────────────────────────────────────────────────────┘
+```
+
+### Metrics Implementation
+
+**Readability (Flesch-Kincaid):**
+```javascript
+// Flesch Reading Ease
+ease = 206.835 - 1.015 * (words / sentences) - 84.6 * (syllables / words);
+
+// Flesch-Kincaid Grade Level
+grade = 0.39 * (words / sentences) + 11.8 * (syllables / words) - 15.59;
+```
+
+**Syllable Estimation:**
+```javascript
+function countSyllables(word) {
+    word = word.toLowerCase().replace(/(?:[^laeiouy]es|ed|[^laeiouy]e)$/, '');
+    word = word.replace(/^y/, '');
+    return word.match(/[aeiouy]{1,2}/g)?.length || 1;
+}
+```
+
+**Reading/Speaking Time:**
+- Reading: 200 words/minute
+- Speaking: 130 words/minute
+
+**Lexical Diversity:**
+- Ratio of unique words to total words (excluding stop words)
+
+**Top Words:**
+- Frequency map, sorted descending, top 10
+- Excludes common stop words (the, a, an, is, are, etc.)
+
+### Word Goal
+
+- Persisted in `electron-store` per document (or global default)
+- Progress bar with percentage
+- Celebration effect when goal is reached (brief confetti animation or green flash)
+
+### Update Cadence
+
+- Re-analyzes on editor content change (debounced at 1000ms)
+- If modal is open, updates live
+- If modal is closed, no computation (zero overhead)
+
+---
+
+## File Summary
+
+| File | Action | Purpose |
+|------|--------|---------|
+| `src/zen-mode.js` | Create | ZenMode class with CM6 extensions |
+| `src/styles-zen.css` | Create | Zen mode styling |
+| `src/sidebar/outline-panel.js` | Create | Outline sidebar panel |
+| `src/analytics/writing-analytics.js` | Create | Analytics computation engine |
+| `src/analytics/analytics-panel.js` | Create | Analytics modal UI |
+| `src/index.html` | Modify | Add outline icon, zen mode button |
+| `src/renderer.js` | Modify | Initialize all three features |
+| `src/editor/codemirror-setup.js` | Modify | Export typewriter + dimming extensions |
+
+## Keyboard Shortcuts
+
+| Shortcut | Feature | Action |
+|----------|---------|--------|
+| F11 | Zen Mode | Toggle on/off |
+| Escape | Zen Mode | Exit (when active) |
+| Ctrl+Shift+O | Outline | Open outline sidebar panel |
+| Ctrl+Shift+A | Analytics | Open analytics modal |
+
+## Dependencies
+
+No new npm dependencies required. All features use:
+- Existing CodeMirror 6 APIs (ViewPlugin, Decoration, scrollIntoView)
+- Existing SidebarManager API
+- Existing ModalManager API
+- Pure JavaScript math for analytics

docs/superpowers/specs/2026-04-14-v5-platform-design.md

@@ -0,0 +1,426 @@
+# MarkdownConverter v5.0 — Platform Design
+
+**Date:** 2026-04-14
+**Status:** Approved
+**Author:** Amit Haridas
+
+## Overview
+
+Transform MarkdownConverter from a monolithic editor into an extensible platform with a plugin system and three feature packs, shipped together as v5.0.
+
+## Subsystems
+
+1. **Plugin System** — Lightweight plugin registry with extension points (sidebar, commands, settings, status bar, export hooks, event bus)
+2. **Writing Studio Plugin** — Manuscript manager, goal tracking, writing sprints, snapshots, smart proofreading
+3. **AI Assistant Plugin** — Multi-provider AI writing assistant (Ollama, LMStudio, GGUF direct with GPU, Anthropic, OpenAI)
+4. **Collaboration Plugin** — Git-based async collaboration, comments/annotations, review requests
+
+## Core Principle
+
+**Existing functionality is never replaced or broken.** The plugin system is additive. All existing keyboard shortcuts, features, and UI remain untouched. Plugin shortcuts use `Ctrl+Alt+` namespace.
+
+---
+
+## 1. Plugin System
+
+### File Structure
+
+```
+src/
+  plugins/
+    plugin-registry.js      # Load, register, lifecycle
+    plugin-api.js            # Base class plugins extend
+    plugin-loader.js         # Discovers and validates manifests
+    built-in/
+      writing-studio/
+        manifest.json
+        index.js
+        panels/
+        components/
+      ai-assistant/
+        manifest.json
+        index.js
+        providers/
+      collaboration/
+        manifest.json
+        index.js
+```
+
+### Manifest Schema
+
+```json
+{
+  "id": "writing-studio",
+  "name": "Writing Studio",
+  "version": "1.0.0",
+  "description": "Manuscript management, goal tracking, writing sprints",
+  "icon": "pen-tool",
+  "extensionPoints": {
+    "sidebar": { "panel": "panels/manuscript-panel.js", "order": 30 },
+    "settings": { "section": "settings/index.js" },
+    "statusBar": { "indicators": ["sprint-timer", "word-goal"] },
+    "commands": [
+      { "id": "start-sprint", "label": "Start Writing Sprint", "shortcut": "Ctrl+Alt+S" },
+      { "id": "take-snapshot", "label": "Take Snapshot", "shortcut": "Ctrl+Alt+N" }
+    ],
+    "exportHooks": {
+      "preExport": "hooks/pre-export.js",
+      "postExport": "hooks/post-export.js"
+    }
+  },
+  "settings": [
+    { "key": "dailyGoal", "type": "number", "default": 1000, "label": "Daily word goal" },
+    { "key": "sprintDuration", "type": "number", "default": 25, "label": "Sprint duration (min)" }
+  ]
+}
+```
+
+### Plugin Lifecycle
+
+1. PluginLoader discovers manifests in `built-in/` + user plugins directory
+2. PluginRegistry validates manifests
+3. Each plugin calls `Plugin.init(context)` receiving scoped API context
+4. Extension points registered (sidebar panels, commands, status bar items)
+5. Plugins activate lazily — sidebar panel loads JS when user clicks tab
+
+### Plugin Context API
+
+Each plugin's `init()` receives:
+
+```javascript
+{
+  sidebar: {
+    registerPanel(id, { icon, title, component })
+  },
+  commands: {
+    register(id, label, handler, shortcut?)
+  },
+  statusBar: {
+    registerIndicator(id, { position, render })
+  },
+  settings: {
+    get(key),                    // plugin-scoped
+    set(key, value),             // auto-persisted via electron-store
+    onChanged(key, callback)
+  },
+  editor: {
+    getContent(),                // current document
+    getSelection(),              // selected text
+    insertAtCursor(text),        // requires opt-in
+    onContentChanged(callback)
+  },
+  events: {
+    on(event, handler),
+    emit(event, data)
+  },
+  exports: {
+    registerPreHook(handler),
+    registerPostHook(handler)
+  },
+  ipc: {
+    invoke(channel, ...args),
+    on(channel, handler)
+  }
+}
+```
+
+### Event Bus Events
+
+Each event has a versioned payload schema. Breaking changes increment the version suffix.
+
+```
+document:opened        → { filePath: string, tabId: string }
+document:saved         → { filePath: string, tabId: string }
+document:changed       → { tabId: string, content: string, wordCount: number }
+editor:selection-changed → { tabId: string, text: string, from: {line,ch}, to: {line,ch} }
+tab:switched           → { tabId: string, filePath: string }
+tab:closed             → { tabId: string, filePath: string }
+export:started         → { format: string, filePath: string }
+export:completed       → { format: string, filePath: string, outputPath: string }
+export:failed          → { format: string, error: string }
+plugin:loaded          → { pluginId: string, version: string }
+plugin:activated       → { pluginId: string }
+plugin:deactivated     → { pluginId: string }
+app:ready              → {}
+app:before-quit        → {}
+```
+
+### Design Rules
+
+- Built-in plugins use the same API as future third-party plugins
+- Lazy activation — sidebar panels don't load until clicked
+- Scoped settings: `plugins.<id>.<key>` in electron-store
+- Plugin commands globally unique — registry rejects duplicate command IDs at load time
+- **Plugin sandboxing**: each plugin handler is wrapped in try/catch. For CPU-intensive operations (AI inference, diff computation), plugins must delegate to main process via IPC. Handlers that block the renderer for >5s trigger a warning notification. Memory-hungry operations (GGUF inference) run in isolated child processes.
+- **Cross-plugin graceful degradation**: plugins check `context.events.hasHandler('ai:analyze')` before emitting cross-plugin requests. If no handler (AI plugin disabled), show a "this feature requires the AI plugin" prompt instead of failing silently. All cross-plugin calls have a 30s timeout with default fallback behavior.
+
+---
+
+## 2. Writing Studio Plugin
+
+### 2A. Manuscript / Project Manager
+
+Folder-based project structure:
+
+```
+~/Manuscripts/
+  my-novel/
+    .project.json          # { title, targets, metadata }
+    01-chapter-one.md
+    02-chapter-two.md
+    characters/
+      protagonist.md
+    research/
+      world-building.md
+    .snapshots/
+      2026-04-14T10-30.json
+```
+
+`.project.json`:
+
+```json
+{
+  "title": "My Novel",
+  "type": "manuscript",
+  "target": { "words": 80000, "deadline": "2026-09-01" },
+  "chapters": [
+    { "file": "01-chapter-one.md", "title": "The Beginning", "status": "draft" }
+  ],
+  "metadata": { "author": "", "genre": "", "synopsis": "" }
+}
+```
+
+Sidebar panel shows project tree with drag-to-reorder, word counts per chapter, target progress bar. "Compile manuscript" exports all chapters as a single document.
+
+### 2B. Goal Tracking & Writing Sprints
+
+- **Status bar**: daily progress bar + sprint timer
+- **Writing sprint**: configurable duration (15/25/30/45/60 min), word count delta, WPM at end
+- **Goal tracking**: daily/weekly word goals, streak tracking, 30-day bar chart
+- **Enhanced analytics**: session tracking, readability scores, productive time-of-day heatmap
+- Data stored in `plugins.writing-studio.history` as date-keyed map
+
+### 2C. Snapshot & Versioning
+
+- `Ctrl+Alt+N` or toolbar button saves snapshot
+- Stored as JSON: `{ timestamp, content, wordCount, cursorPos, label }`
+- Snapshot panel in sidebar: Restore, Diff (side-by-side), auto-snapshot interval
+- Snapshots in `.snapshots/` inside project folder, or app data if no project
+
+### 2D. Smart Proofreading
+
+Delegates to AI plugin via event bus. Writing Studio provides:
+- Right-click context menu: "Check grammar", "Suggest alternatives", "Analyze readability"
+- Inline wavy underline decorations for issues
+- Proofread panel: issues categorized by type with Accept/Dismiss
+
+### Commands
+
+| Command | Shortcut | Action |
+|---------|----------|--------|
+| `start-sprint` | `Ctrl+Alt+S` | Start writing sprint |
+| `stop-sprint` | `Ctrl+Alt+Shift+S` | Stop sprint |
+| `take-snapshot` | `Ctrl+Alt+N` | Save snapshot |
+| `restore-last-snapshot` | `Ctrl+Alt+Z` | Restore latest snapshot |
+| `new-project` | — | Create manuscript project |
+| `compile-manuscript` | `Ctrl+Alt+E` | Export all chapters |
+| `proofread-document` | `Ctrl+Alt+G` | AI proofread |
+
+---
+
+## 3. AI Assistant Plugin
+
+### Provider Architecture
+
+```
+AI Plugin
+  ├── Provider Interface
+  │     ├── complete(prompt, options) → string
+  │     ├── stream(prompt, options) → AsyncIterable
+  │     └── analyze(text, type) → AnalysisResult
+  │
+  ├── Providers
+  │     ├── OllamaProvider      — localhost:11434
+  │     ├── LMStudioProvider    — localhost:1234/v1
+  │     ├── GGUFProvider         — direct llama.cpp with GPU support
+  │     ├── AnthropicProvider    — Claude API
+  │     └── OpenAIProvider       — GPT API
+  │
+  └── Features
+        ├── Grammar/style check
+        ├── Inline auto-complete
+        ├── AI chat panel (sidebar)
+        ├── Document analysis
+        └── Smart commands (command palette)
+```
+
+### Provider Details
+
+**Ollama:** `GET /api/tags` for models, `POST /api/generate` and `POST /api/chat` for inference.
+
+**LMStudio:** OpenAI-compatible API at `localhost:1234/v1`. `GET /v1/models`, standard chat completion format, SSE streaming.
+
+**GGUF Direct (with GPU):**
+- Ships bundled llama.cpp binaries per platform (CUDA, Vulkan, Metal, CPU variants)
+- Auto-detects GPU: CUDA (nvidia-smi), Vulkan driver, Metal (macOS)
+- GPU layer offloading: configurable, auto-suggests based on VRAM vs model size
+- Settings: GPU backend selection, layer count, context length, thread count
+- "Keep model loaded" option for faster repeated requests
+- WASM fallback for sandboxed environments (CPU-only)
+- External binary path for advanced users with custom builds
+- **Process isolation**: llama.cpp runs as a spawned child process (not in main process). If it crashes, detected via exit handler, auto-restarted with notification. GPU memory freed on crash. App remains stable.
+- Process management: spawn in server mode on localhost ephemeral port, clean up on app quit or model unload
+
+**Cloud (Anthropic/OpenAI):**
+- API key stored encrypted via electron safeStorage
+- Token usage tracking with estimated cost
+- Rate limit awareness with request queueing and backoff
+
+### IPC Design
+
+All provider HTTP requests go through main process:
+- No CORS issues
+- API keys never in renderer
+- Main process enforces rate limiting
+- GGUF inference in isolated child process
+
+**Request/response lifecycle:**
+```
+Renderer → ipc.invoke('ai:complete') → Main → HTTP to provider → result → Renderer
+```
+
+**Streaming lifecycle with error handling:**
+```
+Renderer → ipc.invoke('ai:stream', { requestId, prompt })
+         ← Main assigns requestId, returns { requestId }
+         ← ipc.on('ai:chunk', { requestId, text }) — repeated
+         ← ipc.on('ai:done', { requestId }) — success
+         ← ipc.on('ai:error', { requestId, error }) — failure
+
+// Cancellation
+Renderer → ipc.invoke('ai:cancel', { requestId })
+         ← Main aborts HTTP request, emits 'ai:done'
+
+// Orphan cleanup: if renderer disconnects (crash/close),
+// main process detects via 'render-view-deleted' and aborts all active streams.
+// Heartbeat: if no chunk received in 30s, main emits 'ai:error' with timeout.
+```
+
+### Features
+
+1. **Inline suggestions**: ghost text after configurable delay, Tab to accept, Esc to dismiss
+2. **AI chat panel**: sidebar conversation, "Insert" / "Replace selection" buttons
+3. **Document analysis**: grammar, style, tone, with accept/reject per suggestion
+4. **Smart commands**: summarize, generate outline, find inconsistencies, translate, explain code
+
+### Privacy
+
+- Local-first: default provider is Ollama
+- No telemetry: requests go direct to provider
+- Content gating: exclude file types from AI
+- Status bar shows "AI: processing..." with cancel option
+- Cloud usage stats in settings (tokens, cost)
+
+### Cross-Plugin Integration
+
+```javascript
+// Writing Studio calls AI Plugin
+context.events.emit('ai:analyze', { text, type: 'grammar', callback });
+```
+
+---
+
+## 4. Collaboration Plugin
+
+### 4A. Enhanced Git Panel
+
+Upgrades to existing git panel:
+- Remote management (add/remove remotes, push/pull)
+- Branch list and switching
+- Commit history with diff viewer (side-by-side or unified)
+- Conflict resolution UI (accept-ours/accept-theirs/per-edit)
+
+### 4B. Shared Repository Workflow
+
+1. Writer A creates project + initializes git + pushes to shared repo
+2. Writer B clones repo from within MarkdownConverter
+3. Both write on their own branches
+4. Writer A creates review request (simplified PR)
+
+Review request: changed files, word count diff, commit messages. Reviewer can approve, request changes, leave inline comments. Reviews are git branches + comments as git notes.
+
+### 4C. Comments & Annotations
+
+Inline comments stored as JSON in `.comments/` directory (git-tracked):
+```json
+{
+  "id": "uuid",
+  "file": "03-chapter-three.md",
+  "anchor": {
+    "contextBefore": "The hero looked at the horizon and said,",
+    "selectedText": "I will not go quietly into that dark night",
+    "contextAfter": "He turned to face the army alone."
+  },
+  "line": 142,
+  "text": "This dialogue feels unnatural",
+  "author": "amit",
+  "timestamp": "2026-04-14T14:30:00Z",
+  "replies": [],
+  "resolved": false
+}
+```
+
+- **Anchor-based positioning**: comments store `contextBefore`, `selectedText`, and `contextAfter` (not absolute byte offsets). On file change, re-anchor by searching for the context text. If context no longer matches, mark comment as "detached" and show a warning. Falls back to `line` number as rough position.
+- Highlighted text in editor with tooltip on hover
+- Comment panel in sidebar: all unresolved comments across files
+- Resolution workflow: add → address → reply → resolve
+- Resolved comments dim but stay visible
+
+### 4D. Change Notifications
+
+- Status bar indicator: `↓ 3 new commits`
+- Click to see changes, one-click pull
+- Conflicts trigger resolution UI
+- Push button only when local commits ahead of remote
+
+### 4E. Offline-First
+
+All writing happens locally. Git is the sync mechanism. No internet required for writing, commenting, snapshots, or sprints. Push/pull on user action or auto-sync setting.
+
+### Commands
+
+| Command | Shortcut | Action |
+|---------|----------|--------|
+| `collab:commit` | `Ctrl+Shift+G` | Commit with message |
+| `collab:push` | — | Push current branch |
+| `collab:pull` | — | Pull from remote |
+| `collab:add-comment` | `Ctrl+Alt+C` | Comment on selection |
+| `collab:next-comment` | `F8` | Next unresolved comment |
+| `collab:prev-comment` | `Shift+F8` | Previous comment |
+| `collab:create-review` | — | Create review request |
+
+### Cross-Plugin Integration
+
+```javascript
+context.events.emit('snapshot:created', { file, snapshotId });
+context.events.on('project:chapter-opened', (chapter) => { /* load comments */ });
+context.events.on('comment:added', (comment) => { /* AI could suggest fix */ });
+```
+
+---
+
+## Bundle Size Impact
+
+- llama.cpp binaries: ~15MB per GPU variant. Only target platform shipped. GPU variants (CUDA/Vulkan/Metal) downloaded on demand if user enables GGUF direct loading — not bundled by default. Only CPU fallback bundled (~15MB).
+- Plugin system core: ~30KB
+- Each built-in plugin: ~50-100KB
+- Diff library (jsdiff): ~15KB
+- Total estimated increase: ~20-30MB (core), additional ~30-50MB per GPU variant (lazy download)
+
+## Testing Strategy
+
+- Plugin system: unit tests for registry, loader, context API mocking
+- Each plugin: isolated unit tests, integration tests via plugin context
+- AI provider tests: mock HTTP responses, test streaming parsing
+- Git tests: use test repository fixture
+- E2E: verify plugin loading doesn't break existing features

eslint.config.js

@@ -75,6 +75,7 @@ module.exports = [
         jest: 'readonly',
         describe: 'readonly',
         test: 'readonly',
+        it: 'readonly',
         expect: 'readonly',
         beforeEach: 'readonly',
         afterEach: 'readonly',

package.json

@@ -1,6 +1,6 @@
 {
   "name": "markdown-converter",
-  "version": "4.0.0",
+  "version": "4.4.1",
   "description": "Professional Markdown editor and universal file converter with PDF editing, batch processing, and syntax highlighting",
   "main": "src/main.js",
   "scripts": {
@@ -14,12 +14,16 @@
     "format:check": "prettier --check src tests",
     "build": "electron-builder",
     "build:win": "electron-builder --win",
-    "build:win-signed": "cross-env CSC_LINK=code-signing-cert.pfx CSC_KEY_PASSWORD=%CSC_KEY_PASSWORD% electron-builder --win",
+    "build:win-signed": "cross-env CSC_LINK=code-signing-cert.pfx electron-builder --win",
     "build:win-unsigned": "cross-env CSC_IDENTITY_AUTO_DISCOVERY=false electron-builder --win",
+    "create-cert": "powershell -ExecutionPolicy Bypass -File scripts/create-selfsigned-cert.ps1",
     "build:mac": "electron-builder --mac",
     "build:linux": "electron-builder --linux",
+    "build:linux-ci": "electron-builder --linux deb AppImage",
+    "build:local": "electron-builder --linux --win",
     "dist": "electron-builder --publish=never",
     "dist:all": "electron-builder -mwl",
+    "download-tools": "node scripts/download-tools.js",
     "generate-icons": "node scripts/generate-icons.js"
   },
   "keywords": [
@@ -41,7 +45,7 @@
   "devDependencies": {
     "@testing-library/dom": "^10.4.1",
     "cross-env": "^10.0.0",
-    "electron": "^37.4.0",
+    "electron": "^41.1.1",
     "electron-builder": "^26.0.12",
     "eslint": "^9.39.2",
     "eslint-config-prettier": "^10.1.8",
@@ -72,6 +76,7 @@
     "docx4js": "^3.3.0",
     "dompurify": "^3.3.1",
     "electron-store": "^10.1.0",
+    "ffmpeg-static": "^5.3.0",
     "highlight.js": "^11.11.1",
     "html2pdf.js": "^0.14.0",
     "marked": "^17.0.3",
@@ -83,12 +88,19 @@
     "pdfkit": "^0.17.2",
     "pizzip": "^3.2.0",
     "simple-git": "^3.32.3",
-    "tslib": "^2.8.1",
-    "xlsx": "^0.18.5"
+    "tslib": "^2.8.1"
+  },
+  "overrides": {
+    "jszip": "^3.10.1",
+    "nth-check": "^2.1.1",
+    "lodash.pick": "npm:lodash@^4.17.21",
+    "lodash-es": "^4.18.1",
+    "lodash": "^4.17.21"
   },
   "build": {
     "appId": "com.concreteinfo.markdownconverter",
     "productName": "MarkdownConverter",
+    "copyright": "Copyright (C) 2024-2025 ConcreteInfo",
     "directories": {
       "output": "dist"
     },
@@ -100,6 +112,10 @@
       "node_modules/**/*",
       "package.json"
     ],
+    "asarUnpack": [
+      "node_modules/ffmpeg-static/**"
+    ],
+    "extraFiles": [],
     "fileAssociations": [
       {
         "ext": "md",
@@ -150,7 +166,12 @@
       ],
       "artifactName": "${productName}-${version}-${arch}.${ext}",
       "requestedExecutionLevel": "asInvoker",
-      "signAndEditExecutable": false
+      "legalTrademarks": "Copyright (C) 2024-2025 ConcreteInfo",
+      "verifyUpdateCodeSignature": false,
+      "signAndEditExecutable": false,
+      "extraFiles": [
+        { "from": "bin/win32/pandoc.exe", "to": "bin/pandoc.exe" }
+      ]
     },
     "nsis": {
       "oneClick": false,
@@ -172,29 +193,21 @@
       "target": [
         "deb",
         "AppImage",
-        "snap",
-        "rpm"
+        "snap"
       ],
       "category": "Utility",
-      "maintainer": "ConcreteInfo <amit.wh@gmail.com>"
+      "maintainer": "ConcreteInfo <amit.wh@gmail.com>",
+      "extraFiles": [
+        { "from": "bin/linux/pandoc", "to": "bin/pandoc" }
+      ]
     },
     "deb": {
       "depends": [
-        "pandoc",
-        "ffmpeg",
         "imagemagick",
         "libreoffice-common"
       ],
       "description": "Professional Markdown editor and universal file converter",
       "maintainer": "ConcreteInfo <amit.wh@gmail.com>"
-    },
-    "rpm": {
-      "depends": [
-        "pandoc",
-        "ffmpeg",
-        "ImageMagick",
-        "libreoffice-core"
-      ]
     }
   }
 }

scripts/create-selfsigned-cert.ps1

@@ -0,0 +1,59 @@
+# create-selfsigned-cert.ps1
+# Generates a self-signed code-signing certificate for local/development builds.
+#
+# Usage:
+#   powershell -ExecutionPolicy Bypass -File scripts/create-selfsigned-cert.ps1
+#   npm run create-cert
+#
+# Then build with:
+#   $env:CSC_LINK="code-signing-cert.pfx"; $env:CSC_KEY_PASSWORD="YourPassword"; npm run build:win-signed
+#
+# NOTE: Self-signed certificates will still show a SmartScreen warning for end users.
+# For production releases, obtain an OV or EV certificate from a trusted CA
+# (DigiCert, Sectigo, Certum, etc.). EV certificates bypass SmartScreen immediately.
+# Open-source projects can apply for free signing at https://signpath.io/
+
+param(
+    [string]$CertPassword = "MarkdownConverter2025",
+    [string]$OutputFile   = "code-signing-cert.pfx",
+    [string]$Subject      = "CN=ConcreteInfo, O=ConcreteInfo, L=India, C=IN"
+)
+
+Write-Host "Creating self-signed code-signing certificate..." -ForegroundColor Cyan
+
+# Create the certificate in the current user's certificate store
+$cert = New-SelfSignedCertificate `
+    -Type CodeSigningCert `
+    -Subject $Subject `
+    -CertStoreLocation "Cert:\CurrentUser\My" `
+    -NotAfter (Get-Date).AddYears(3) `
+    -HashAlgorithm SHA256 `
+    -KeyLength 4096 `
+    -KeyUsage DigitalSignature
+
+if (-not $cert) {
+    Write-Error "Failed to create certificate."
+    exit 1
+}
+
+Write-Host "Certificate created: $($cert.Thumbprint)" -ForegroundColor Green
+
+# Export to PFX
+$securePassword = ConvertTo-SecureString -String $CertPassword -Force -AsPlainText
+$exportPath = Join-Path (Get-Location) $OutputFile
+
+Export-PfxCertificate -Cert $cert -FilePath $exportPath -Password $securePassword | Out-Null
+
+if (Test-Path $exportPath) {
+    Write-Host "Certificate exported to: $exportPath" -ForegroundColor Green
+    Write-Host ""
+    Write-Host "To build a signed release:" -ForegroundColor Yellow
+    Write-Host '  $env:CSC_LINK="code-signing-cert.pfx"' -ForegroundColor White
+    Write-Host "  `$env:CSC_KEY_PASSWORD=`"$CertPassword`"" -ForegroundColor White
+    Write-Host "  npm run build:win-signed" -ForegroundColor White
+    Write-Host ""
+    Write-Host "IMPORTANT: Add code-signing-cert.pfx to .gitignore!" -ForegroundColor Red
+} else {
+    Write-Error "Export failed."
+    exit 1
+}

scripts/download-tools.js

@@ -0,0 +1,148 @@
+#!/usr/bin/env node
+/**
+ * Downloads pandoc binary for the current build platform.
+ * Run automatically via `npm run download-tools` before building.
+ * Skips download if binary already exists (idempotent).
+ */
+
+const https = require('https');
+const http = require('http');
+const fs = require('fs');
+const path = require('path');
+const os = require('os');
+const { execSync } = require('child_process');
+
+const PANDOC_VERSION = '3.9.0.2';
+
+const PANDOC_CONFIG = {
+  linux: {
+    url: `https://github.com/jgm/pandoc/releases/download/${PANDOC_VERSION}/pandoc-${PANDOC_VERSION}-linux-amd64.tar.gz`,
+    archiveExt: '.tar.gz',
+    destFile: 'pandoc',
+    extract(archivePath, destDir) {
+      const tmpDir = path.join(os.tmpdir(), `pandoc-${Date.now()}`);
+      fs.mkdirSync(tmpDir, { recursive: true });
+      execSync(`tar -xzf "${archivePath}" -C "${tmpDir}" pandoc-${PANDOC_VERSION}/bin/pandoc`);
+      const src = path.join(tmpDir, `pandoc-${PANDOC_VERSION}`, 'bin', 'pandoc');
+      fs.copyFileSync(src, path.join(destDir, 'pandoc'));
+      fs.chmodSync(path.join(destDir, 'pandoc'), 0o755);
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    },
+  },
+  win32: {
+    url: `https://github.com/jgm/pandoc/releases/download/${PANDOC_VERSION}/pandoc-${PANDOC_VERSION}-windows-x86_64.zip`,
+    archiveExt: '.zip',
+    destFile: 'pandoc.exe',
+    extract(archivePath, destDir) {
+      const tmpDir = path.join(os.tmpdir(), `pandoc-${Date.now()}`);
+      fs.mkdirSync(tmpDir, { recursive: true });
+      execSync(
+        `powershell -Command "Expand-Archive -Force '${archivePath}' '${tmpDir}'"`,
+      );
+      const src = path.join(tmpDir, `pandoc-${PANDOC_VERSION}`, 'pandoc.exe');
+      fs.copyFileSync(src, path.join(destDir, 'pandoc.exe'));
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    },
+  },
+  darwin: {
+    url: `https://github.com/jgm/pandoc/releases/download/${PANDOC_VERSION}/pandoc-${PANDOC_VERSION}-x86_64-macOS.zip`,
+    archiveExt: '.zip',
+    destFile: 'pandoc',
+    extract(archivePath, destDir) {
+      const tmpDir = path.join(os.tmpdir(), `pandoc-${Date.now()}`);
+      fs.mkdirSync(tmpDir, { recursive: true });
+      execSync(`unzip -o "${archivePath}" -d "${tmpDir}"`);
+      const src = path.join(tmpDir, `pandoc-${PANDOC_VERSION}`, 'bin', 'pandoc');
+      fs.copyFileSync(src, path.join(destDir, 'pandoc'));
+      fs.chmodSync(path.join(destDir, 'pandoc'), 0o755);
+      fs.rmSync(tmpDir, { recursive: true, force: true });
+    },
+  },
+};
+
+function download(url, destPath) {
+  return new Promise((resolve, reject) => {
+    const file = fs.createWriteStream(destPath);
+    let received = 0;
+    let total = 0;
+    let lastPct = -1;
+
+    function get(redirectUrl) {
+      const client = redirectUrl.startsWith('https://') ? https : http;
+      client
+        .get(redirectUrl, (res) => {
+          if (res.statusCode === 301 || res.statusCode === 302) {
+            get(res.headers.location);
+            return;
+          }
+          if (res.statusCode !== 200) {
+            reject(new Error(`HTTP ${res.statusCode} for ${redirectUrl}`));
+            return;
+          }
+          total = parseInt(res.headers['content-length'] || '0', 10);
+          res.on('data', (chunk) => {
+            received += chunk.length;
+            if (total > 0) {
+              const pct = Math.floor((received / total) * 100);
+              if (pct !== lastPct && pct % 10 === 0) {
+                process.stdout.write(`  ${pct}%\r`);
+                lastPct = pct;
+              }
+            }
+          });
+          res.pipe(file);
+          file.on('finish', () => {
+            file.close();
+            process.stdout.write('  100%\n');
+            resolve();
+          });
+        })
+        .on('error', (err) => {
+          fs.unlink(destPath, () => {});
+          reject(err);
+        });
+    }
+    get(url);
+  });
+}
+
+async function downloadPandoc() {
+  const platform = process.platform;
+  const config = PANDOC_CONFIG[platform];
+
+  if (!config) {
+    console.log(`[download-tools] No pandoc config for platform "${platform}" — skipping.`);
+    return;
+  }
+
+  const destDir = path.join(__dirname, '..', 'bin', platform);
+  const destFile = path.join(destDir, config.destFile);
+
+  if (fs.existsSync(destFile)) {
+    console.log(`[download-tools] pandoc already present at ${destFile} — skipping.`);
+    return;
+  }
+
+  fs.mkdirSync(destDir, { recursive: true });
+
+  const tmpArchive = path.join(os.tmpdir(), `pandoc-download${config.archiveExt}`);
+
+  console.log(`[download-tools] Downloading pandoc ${PANDOC_VERSION} for ${platform}...`);
+  await download(config.url, tmpArchive);
+
+  console.log(`[download-tools] Extracting to ${destDir}...`);
+  config.extract(tmpArchive, destDir);
+
+  try {
+    fs.unlinkSync(tmpArchive);
+  } catch (_) {
+    /* ignore */
+  }
+
+  console.log(`[download-tools] pandoc ready: ${destFile}`);
+}
+
+downloadPandoc().catch((err) => {
+  console.error('[download-tools] FAILED:', err.message);
+  process.exit(1);
+});

src/adapters/electron/fs.js

@@ -0,0 +1,111 @@
+/**
+ * Electron File System Adapter
+ *
+ * Implements file system operations for Electron using IPC.
+ * This abstracts file operations to enable easier testing and migration.
+ *
+ * @version 4.4.1
+ */
+
+/**
+ * Electron File System Adapter
+ * @type {import('../types').FileSystemAdapter}
+ */
+const electronFsAdapter = {
+    /**
+     * Read file content
+     * @param {string} path - File path
+     * @returns {Promise<string>} File content
+     */
+    async readFile(path) {
+        return await window.electronAPI.file.read(path);
+    },
+
+    /**
+     * Write content to file
+     * @param {string} path - File path
+     * @param {string} content - File content
+     * @returns {Promise<void>}
+     */
+    async writeFile(path, content) {
+        return await window.electronAPI.file.write(path, content);
+    },
+
+    /**
+     * Delete file
+     * @param {string} path - File path
+     * @returns {Promise<void>}
+     */
+    async deleteFile(path) {
+        return await window.electronAPI.file.delete(path);
+    },
+
+    /**
+     * Ensure directory exists
+     * @param {string} path - Directory path
+     * @returns {Promise<void>}
+     */
+    async ensureDir(path) {
+        return await window.electronAPI.file.ensureDir(path);
+    },
+
+    /**
+     * List directory contents
+     * @param {string} path - Directory path
+     * @returns {Promise<Array<import('../types').FileInfo>>}
+     */
+    async listDirectory(path) {
+        const result = await window.electronAPI.invoke('list-directory', path);
+        if (!result?.entries) {
+            return [];
+        }
+
+        return result.entries.map((entry) => ({
+            name: entry.name,
+            isDir: entry.isDirectory,
+            size: entry.size ?? 0,
+            modified: entry.modified ?? 0,
+            path: entry.path
+        }));
+    },
+
+    /**
+     * Check if path exists
+     * @param {string} path - Path to check
+     * @returns {Promise<boolean>}
+     */
+    async exists(path) {
+        return await window.electronAPI.file.exists(path);
+    },
+
+    /**
+     * Check if path is a directory
+     * @param {string} path - Path to check
+     * @returns {Promise<boolean>}
+     */
+    async isDirectory(path) {
+        return await window.electronAPI.file.isDirectory(path);
+    },
+
+    /**
+     * Copy file or directory
+     * @param {string} source - Source path
+     * @param {string} dest - Destination path
+     * @returns {Promise<void>}
+     */
+    async copy(source, dest) {
+        return await window.electronAPI.file.copy(source, dest);
+    },
+
+    /**
+     * Move file or directory
+     * @param {string} source - Source path
+     * @param {string} dest - Destination path
+     * @returns {Promise<void>}
+     */
+    async move(source, dest) {
+        return await window.electronAPI.file.move(source, dest);
+    }
+};
+
+module.exports = { electronFsAdapter };

src/adapters/types.js

@@ -0,0 +1,133 @@
+/**
+ * Platform Adapter Type Definitions
+ *
+ * This module defines the interfaces for platform-specific operations.
+ * Adapters abstract file system, conversion, and system operations
+ * to enable easier testing and future platform migration.
+ *
+ * @version 4.4.1
+ */
+
+/**
+ * @typedef {Object} FileInfo
+ * @property {string} name - File or directory name
+ * @property {boolean} isDir - True if directory
+ * @property {number} size - File size in bytes
+ * @property {number} modified - Last modified timestamp (ms since epoch)
+ */
+
+/**
+ * @typedef {Object} WatchEvent
+ * @property {string} type - Event type ('add', 'change', 'unlink', 'addDir', 'unlinkDir')
+ * @property {string} path - Affected file/directory path
+ */
+
+/**
+ * @typedef {Object} ConversionOptions
+ * @property {string} format - Output format (pdf, docx, html, etc.)
+ * @property {string} [pdfEngine] - PDF engine for PDF export (xelatex, pdflatex, etc.)
+ * @property {string} [template] - Word template path for DOCX
+ * @property {string} [geometry] - Page geometry for PDF (e.g., 'margin=1in')
+ * @property {string} [header] - Header content
+ * @property {string} [footer] - Footer content
+ * @property {boolean} [toc] - Include table of contents
+ */
+
+/**
+ * @typedef {Object} ConversionResult
+ * @property {string} input - Input file path
+ * @property {string} output - Output file path
+ * @property {boolean} success - Whether conversion succeeded
+ * @property {string} [error] - Error message if failed
+ */
+
+/**
+ * @typedef {Object} PlatformCapabilities
+ * @property {boolean} hasPandoc - Pandoc is available
+ * @property {boolean} hasFfmpeg - FFmpeg is available
+ * @property {boolean} hasLibreOffice - LibreOffice is available
+ * @property {boolean} hasDirectFs - Direct file system access
+ * @property {boolean} hasSystemNotifications - System notifications available
+ * @property {boolean} hasPdfJs - PDF.js available for PDF viewing
+ */
+
+/**
+ * @typedef {Object} DialogOptions
+ * @property {string} [title] - Dialog title
+ * @property {string} [defaultPath] - Default path
+ * @property {string[]} [filters] - File filters [{ name: 'Markdown', extensions: ['md'] }]
+ * @property {string} [buttonLabel] - Custom button label
+ */
+
+/**
+ * @typedef {Object} SystemInfo
+ * @property {string} platform - Operating system (win32, darwin, linux)
+ * @property {string} homeDir - User home directory
+ * @property {string} documentsDir - Documents directory
+ * @property {string} downloadsDir - Downloads directory
+ * @property {string} tempDir - Temporary directory
+ * @property {string} appVersion - Application version
+ */
+
+/**
+ * @typedef {Object} FileSystemAdapter
+ * @property {(path: string) => Promise<string>} readFile - Read file content
+ * @property {(path: string, content: string) => Promise<void>} writeFile - Write file content
+ * @property {(path: string) => Promise<void>} deleteFile - Delete file
+ * @property {(path: string) => Promise<void>} ensureDir - Ensure directory exists
+ * @property {(path: string) => Promise<FileInfo[]>} listDirectory - List directory contents
+ * @property {(path: string) => Promise<boolean>} exists - Check if path exists
+ * @property {(path: string) => Promise<boolean>} isDirectory - Check if path is directory
+ * @property {(source: string, dest: string) => Promise<void>} copy - Copy file or directory
+ * @property {(source: string, dest: string) => Promise<void>} move - Move file or directory
+ * @property {(path: string, callback: (event: WatchEvent) => void) => () => void>} [watchDirectory] - Watch directory for changes
+ */
+
+/**
+ * @typedef {Object} ConversionAdapter
+ * @property {(input: string, output: string, options: ConversionOptions) => Promise<void>} convertFile - Convert single file
+ * @property {(files: string[], outputDir: string, options: ConversionOptions) => Promise<ConversionResult[]>} batchConvert - Batch convert files
+ * @property {() => Promise<boolean>} checkPandoc - Check if Pandoc is available
+ * @property {() => Promise<boolean>} checkFfmpeg - Check if FFmpeg is available
+ * @property {() => Promise<boolean>} checkLibreOffice - Check if LibreOffice is available
+ */
+
+/**
+ * @typedef {Object} DialogAdapter
+ * @property {(options?: DialogOptions) => Promise<string|null>} showOpenDialog - Show open file dialog
+ * @property {(options?: DialogOptions) => Promise<string[]>} showOpenDialogMulti - Show multi-select open dialog
+ * @property {(options?: DialogOptions) => Promise<string|null>} showSaveDialog - Show save file dialog
+ * @property {(message: string, type?: string) => Promise<void>} showMessage - Show message dialog
+ * @property {(message: string, type?: string) => Promise<boolean>} showConfirm - Show confirmation dialog
+ */
+
+/**
+ * @typedef {Object} SystemAdapter
+ * @property {() => Promise<SystemInfo>} getSystemInfo - Get system information
+ * @property {(title: string, body: string) => Promise<void>} showNotification - Show system notification
+ * @property {(url: string) => Promise<void>} openExternal - Open URL in default browser
+ * @property {(path: string) => Promise<void>} openInExplorer - Open path in file explorer
+ * @property {(path: string) => Promise<void>} openInDefaultApp - Open path in default application
+ */
+
+/**
+ * @typedef {Object} PdfAdapter
+ * @property {(path: string) => Promise<Object>} loadDocument - Load PDF document
+ * @property {(doc: Object, pageNum: number, canvas: HTMLCanvasElement, scale: number, rotation: number) => Promise<void>} renderPage - Render PDF page to canvas
+ * @property {(operations: Object) => Promise<void>} processOperation - Process PDF operation (merge, split, etc.)
+ */
+
+/**
+ * @typedef {Object} PlatformAdapter
+ * @property {string} name - Platform name ('electron', 'web', 'tauri', 'flutter')
+ * @property {FileSystemAdapter} fs - File system operations
+ * @property {ConversionAdapter} convert - Conversion operations
+ * @property {DialogAdapter} dialog - Dialog operations
+ * @property {SystemAdapter} system - System operations
+ * @property {PdfAdapter} [pdf] - PDF operations (optional, not available on all platforms)
+ * @property {PlatformCapabilities} capabilities - Platform capabilities
+ */
+
+module.exports = {
+    // Type definitions are JSDoc only, no runtime exports needed
+};

src/analytics/analytics-panel.js

@@ -0,0 +1,112 @@
+/**
+ * Writing Analytics Panel — modal overlay displaying analytics dashboard
+ */
+
+const { analyze } = require('./writing-analytics');
+
+function showAnalyticsModal(tabManager) {
+    const existing = document.getElementById('analytics-modal');
+    if (existing) existing.remove();
+
+    const content = tabManager.getEditorContent();
+    const metrics = analyze(content);
+
+    const overlay = document.createElement('div');
+    overlay.id = 'analytics-modal';
+    overlay.className = 'analytics-overlay';
+
+    const maxCount = metrics.topWords.length > 0 ? metrics.topWords[0].count : 1;
+
+    overlay.innerHTML = `
+        <div class="analytics-modal">
+            <div class="analytics-header">
+                <h2>Writing Analytics</h2>
+                <button class="analytics-close" title="Close">&times;</button>
+            </div>
+            <div class="analytics-body">
+                <div class="analytics-section">
+                    <h3>Readability</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Flesch Reading Ease</span>
+                        <span class="analytics-value">${metrics.fleschEase}<small>${metrics.readabilityLabel}</small></span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Grade Level</span>
+                        <span class="analytics-value">${metrics.fleschGrade}</span>
+                    </div>
+                    <div class="readability-meter">
+                        <div class="readability-fill" style="width: ${Math.max(0, Math.min(100, metrics.fleschEase))}%"></div>
+                    </div>
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Timing</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Reading Time</span>
+                        <span class="analytics-value">~${metrics.readingTime} min</span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Speaking Time</span>
+                        <span class="analytics-value">~${metrics.speakingTime} min</span>
+                    </div>
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Structure</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Sentences</span>
+                        <span class="analytics-value">${metrics.sentenceCount} &bull; Paragraphs: ${metrics.paragraphCount}</span>
+                    </div>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Avg Sentence</span>
+                        <span class="analytics-value">${metrics.avgSentenceLength} words</span>
+                    </div>
+                    ${metrics.longestSentenceLength > 0 ? `
+                    <div class="analytics-row analytics-longest">
+                        <span class="analytics-label">Longest (${metrics.longestSentenceLength} words)</span>
+                        <span class="analytics-value analytics-sentence-preview">${escapeHtml(metrics.longestSentence)}</span>
+                    </div>` : ''}
+                </div>
+
+                <div class="analytics-section">
+                    <h3>Vocabulary</h3>
+                    <div class="analytics-row">
+                        <span class="analytics-label">Unique</span>
+                        <span class="analytics-value">${metrics.uniqueWordCount} / ${metrics.wordCount}<small>${metrics.lexicalDiversity}%</small></span>
+                    </div>
+                    ${metrics.topWords.length > 0 ? `
+                    <div class="word-cloud">
+                        ${metrics.topWords.map(w => {
+                            const scale = 13 + Math.round((w.count / maxCount) * 3);
+                            return `<span class="word-tag" style="font-size:${scale}px">${escapeHtml(w.word)}<small>${w.count}</small></span>`;
+                        }).join('')}
+                    </div>` : ''}
+                </div>
+            </div>
+        </div>
+    `;
+
+    const closeBtn = overlay.querySelector('.analytics-close');
+    closeBtn.addEventListener('click', () => overlay.remove());
+    overlay.addEventListener('click', (e) => {
+        if (e.target === overlay) overlay.remove();
+    });
+
+    const escHandler = (e) => {
+        if (e.key === 'Escape') {
+            overlay.remove();
+            document.removeEventListener('keydown', escHandler);
+        }
+    };
+    document.addEventListener('keydown', escHandler);
+
+    document.body.appendChild(overlay);
+}
+
+function escapeHtml(str) {
+    const div = document.createElement('div');
+    div.textContent = str;
+    return div.innerHTML;
+}
+
+module.exports = { showAnalyticsModal };

src/analytics/writing-analytics.js

@@ -0,0 +1,127 @@
+/**
+ * Writing Analytics — pure computation engine
+ * No DOM dependencies. Exported analyze(text) returns a metrics object.
+ */
+
+const STOP_WORDS = new Set([
+    'the', 'a', 'an', 'is', 'are', 'was', 'were', 'be', 'been',
+    'have', 'has', 'had', 'do', 'does', 'did', 'will', 'would',
+    'could', 'should', 'to', 'of', 'in', 'for', 'on', 'with',
+    'at', 'by', 'from', 'as', 'and', 'or', 'but', 'if', 'it',
+    'its', 'this', 'that', 'these', 'those', 'i', 'me', 'my',
+    'we', 'our', 'you', 'your', 'he', 'him', 'his', 'she', 'her',
+    'they', 'them', 'their', 'not', 'no', 'so', 'than', 'too',
+    'very', 'also', 'just', 'about', 'up', 'out', 'what', 'which', 'who'
+]);
+
+function countSyllables(word) {
+    word = word.toLowerCase().replace(/(?:[^laeiouy]es|ed|[^laeiouy]e)$/, '');
+    word = word.replace(/^y/, '');
+    return word.match(/[aeiouy]{1,2}/gi)?.length || 1;
+}
+
+function extractWords(text) {
+    return text.match(/[a-zA-Z]+(?:['-][a-zA-Z]+)*/g) || [];
+}
+
+function getReadabilityLabel(score) {
+    if (score >= 90) return 'Very Easy';
+    if (score >= 70) return 'Easy';
+    if (score >= 50) return 'Standard';
+    if (score >= 30) return 'Difficult';
+    return 'Very Difficult';
+}
+
+function analyze(text) {
+    if (!text || !text.trim()) {
+        return {
+            wordCount: 0,
+            sentenceCount: 0,
+            paragraphCount: 0,
+            fleschEase: 0,
+            fleschGrade: 0,
+            readabilityLabel: 'N/A',
+            readingTime: 0,
+            speakingTime: 0,
+            uniqueWordCount: 0,
+            lexicalDiversity: 0,
+            avgSentenceLength: 0,
+            longestSentence: '',
+            longestSentenceLength: 0,
+            topWords: []
+        };
+    }
+
+    const words = extractWords(text);
+    const wordCount = words.length;
+
+    const sentences = text.split(/[.!?]+/).map(s => s.trim()).filter(Boolean);
+    const sentenceCount = Math.max(sentences.length, 1);
+
+    const paragraphs = text.split(/\n\s*\n/).map(p => p.trim()).filter(Boolean);
+    const paragraphCount = Math.max(paragraphs.length, 1);
+
+    let totalSyllables = 0;
+    for (const w of words) {
+        totalSyllables += countSyllables(w);
+    }
+
+    const fleschEase = Math.round((206.835 - 1.015 * (wordCount / sentenceCount) - 84.6 * (totalSyllables / wordCount)) * 10) / 10;
+    const fleschGrade = Math.round((0.39 * (wordCount / sentenceCount) + 11.8 * (totalSyllables / wordCount) - 15.59) * 10) / 10;
+    const readabilityLabel = getReadabilityLabel(fleschEase);
+
+    const readingTime = Math.ceil(wordCount / 200);
+    const speakingTime = Math.ceil(wordCount / 130);
+
+    const uniqueWords = new Set(words.map(w => w.toLowerCase()));
+    const uniqueWordCount = uniqueWords.size;
+    const lexicalDiversity = wordCount > 0 ? Math.round((uniqueWordCount / wordCount) * 1000) / 10 : 0;
+
+    const avgSentenceLength = Math.round((wordCount / sentenceCount) * 10) / 10;
+
+    let longestSentence = '';
+    let longestSentenceLength = 0;
+    for (const s of sentences) {
+        const sWords = extractWords(s);
+        if (sWords.length > longestSentenceLength) {
+            longestSentenceLength = sWords.length;
+            longestSentence = s.trim();
+        }
+    }
+
+    if (longestSentence.length > 80) {
+        longestSentence = longestSentence.substring(0, 80) + '...';
+    }
+
+    const wordFreq = {};
+    for (const w of words) {
+        const lower = w.toLowerCase();
+        if (!STOP_WORDS.has(lower) && lower.length > 1) {
+            wordFreq[lower] = (wordFreq[lower] || 0) + 1;
+        }
+    }
+
+    const topWords = Object.entries(wordFreq)
+        .sort((a, b) => b[1] - a[1])
+        .slice(0, 10)
+        .map(([word, count]) => ({ word, count }));
+
+    return {
+        wordCount,
+        sentenceCount,
+        paragraphCount,
+        fleschEase,
+        fleschGrade,
+        readabilityLabel,
+        readingTime,
+        speakingTime,
+        uniqueWordCount,
+        lexicalDiversity,
+        avgSentenceLength,
+        longestSentence,
+        longestSentenceLength,
+        topWords
+    };
+}
+
+module.exports = { analyze };

src/editor/codemirror-setup.js

@@ -33,6 +33,19 @@ const {
 } = require('@codemirror/language');
 const { oneDark } = require('@codemirror/theme-one-dark');
 
+// Custom theme for JetBrains Mono font
+const jetBrainsMonoTheme = EditorView.theme({
+  '&': {
+    fontFamily: "'JetBrains Mono', 'Fira Code', 'SF Mono', Monaco, 'Courier New', monospace"
+  },
+  '.cm-content': {
+    fontFamily: 'inherit'
+  },
+  '.cm-scroller': {
+    fontFamily: 'inherit'
+  }
+});
+
 /**
  * Create a CodeMirror 6 editor instance.
  *
@@ -46,6 +59,11 @@ const { oneDark } = require('@codemirror/theme-one-dark');
  * @returns {EditorView} the created editor view
  */
 function createEditor(parentElement, options = {}) {
+  console.log('[createEditor] Called with parentElement:', parentElement?.id, 'dimensions:', parentElement?.clientWidth, 'x', parentElement?.clientHeight);
+  if (!parentElement) {
+    console.error('[createEditor] ERROR: parentElement is null or undefined!');
+    return null;
+  }
   const {
     content = '',
     onChange = () => {},
@@ -64,6 +82,7 @@ function createEditor(parentElement, options = {}) {
     highlightSelectionMatches(),
     autocompletion(),
     foldGutter(),
+    jetBrainsMonoTheme,
     keymap.of([
       ...defaultKeymap,
       ...historyKeymap,

src/index.html

@@ -2,18 +2,27 @@
 <html lang="en">
 <head>
     <meta charset="UTF-8">
-    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline' https://cdnjs.cloudflare.com; img-src 'self' data: blob: file:; font-src 'self' data:; connect-src 'self' https://www.plantuml.com;">
+    <!-- CSP: unsafe-inline/unsafe-eval required for marked.js extensions and Mermaid -->
+    <!-- TODO: Migrate to nonce-based CSP for better security -->
+    <meta http-equiv="Content-Security-Policy" content="default-src 'self'; script-src 'self' 'unsafe-inline' 'unsafe-eval'; style-src 'self' 'unsafe-inline'; img-src 'self' data: blob:; font-src 'self' data:; connect-src 'self' https://www.plantuml.com;">
     <meta name="viewport" content="width=device-width, initial-scale=1.0">
     <title>MarkdownConverter</title>
+    <!-- Design tokens - loaded first for CSS variable availability -->
+    <link rel="stylesheet" href="styles/tokens.css">
+    <link rel="stylesheet" href="styles/modal.css">
     <link rel="stylesheet" href="fonts.css">
     <link rel="stylesheet" href="styles.css">
     <link rel="stylesheet" href="styles-modern.css">
     <link rel="stylesheet" href="styles-concreteinfo.css">
     <link rel="stylesheet" href="styles-sidebar.css">
+    <link rel="stylesheet" href="styles-zen.css">
     <link rel="stylesheet" href="styles-welcome.css">
+    <link rel="stylesheet" href="styles-zen.css">
     <link rel="stylesheet" href="../node_modules/highlight.js/styles/default.css">
 </head>
 <body>
+    <!-- Skip link for keyboard navigation -->
+    <a href="#editor-container" class="skip-link">Skip to editor</a>
     <div class="container">
         <!-- App Header with ConcreteInfo Logo -->
         <div class="app-header" id="app-header">
@@ -22,34 +31,34 @@
                 <span class="app-title">MarkdownConverter</span>
             </div>
             <div class="app-header-right">
-                <span class="app-version">v4.0.0</span>
+                <span class="app-version" id="app-version-display"></span>
             </div>
         </div>
-        <div class="tab-bar" id="tab-bar">
-            <div class="tab active" data-tab-id="1">
+        <div class="tab-bar" id="tab-bar" role="tablist" aria-label="Document tabs">
+            <div class="tab active" data-tab-id="1" role="tab" aria-selected="true">
                 <span class="tab-title">Untitled</span>
-                <button class="tab-close" title="Close tab">×</button>
+                <button class="tab-close" title="Close tab" aria-label="Close tab">×</button>
             </div>
-            <button class="new-tab-button" id="new-tab-btn" title="New tab">+</button>
+            <button class="new-tab-button" id="new-tab-btn" title="New tab" aria-label="Create new tab">+</button>
         </div>
         <div class="toolbar">
             <div class="toolbar-group">
                 <!-- Format: Bold, Italic, Strikethrough -->
-                <button id="btn-bold" title="Bold (Ctrl+B)">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-bold" title="Bold (Ctrl+B)" aria-label="Bold">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <path d="M6 4h8a4 4 0 0 1 4 4 4 4 0 0 1-4 4H6z"></path>
                         <path d="M6 12h9a4 4 0 0 1 4 4 4 4 0 0 1-4 4H6z"></path>
                     </svg>
                 </button>
-                <button id="btn-italic" title="Italic (Ctrl+I)">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-italic" title="Italic (Ctrl+I)" aria-label="Italic">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <line x1="19" y1="4" x2="10" y2="4"></line>
                         <line x1="14" y1="20" x2="5" y2="20"></line>
                         <line x1="15" y1="4" x2="9" y2="20"></line>
                     </svg>
                 </button>
-                <button id="btn-strikethrough" title="Strikethrough">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-strikethrough" title="Strikethrough" aria-label="Strikethrough">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <path d="M16 4H9a3 3 0 0 0-2.83 4"></path>
                         <path d="M14 12a4 4 0 0 1 0 8H6"></path>
                         <line x1="4" y1="12" x2="20" y2="12"></line>
@@ -59,15 +68,15 @@
             <div class="toolbar-separator"></div>
             <div class="toolbar-group">
                 <!-- Structure: Heading, List, Quote -->
-                <button id="btn-heading" title="Heading">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-heading" title="Heading" aria-label="Insert heading">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <polyline points="4 7 4 4 20 4 20 7"></polyline>
                         <line x1="9" y1="20" x2="15" y2="20"></line>
                         <line x1="12" y1="4" x2="12" y2="20"></line>
                     </svg>
                 </button>
-                <button id="btn-list" title="List">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-list" title="List" aria-label="Insert list">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <line x1="8" y1="6" x2="21" y2="6"></line>
                         <line x1="8" y1="12" x2="21" y2="12"></line>
                         <line x1="8" y1="18" x2="21" y2="18"></line>
@@ -76,8 +85,8 @@
                         <line x1="3" y1="18" x2="3.01" y2="18"></line>
                     </svg>
                 </button>
-                <button id="btn-quote" title="Quote">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-quote" title="Quote" aria-label="Insert quote">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <path d="M3 21c3 0 7-1 7-8V5c0-1.25-.756-2.017-2-2H4c-1.25 0-2 .75-2 1.972V11c0 1.25.75 2 2 2 1 0 1 0 1 1v1c0 1-1 2-2 2s-1 .008-1 1.031V20c0 1 0 1 1 1z"></path>
                         <path d="M15 21c3 0 7-1 7-8V5c0-1.25-.757-2.017-2-2h-4c-1.25 0-2 .75-2 1.972V11c0 1.25.75 2 2 2h.75c0 2.25.25 4-2.75 4v3c0 1 0 1 1 1z"></path>
                     </svg>
@@ -86,27 +95,27 @@
             <div class="toolbar-separator"></div>
             <div class="toolbar-group">
                 <!-- Insert: Link, Code, Code Block, Table, HR -->
-                <button id="btn-link" title="Link">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-link" title="Link" aria-label="Insert link">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <path d="M10 13a5 5 0 0 0 7.54.54l3-3a5 5 0 0 0-7.07-7.07l-1.72 1.71"></path>
                         <path d="M14 11a5 5 0 0 0-7.54-.54l-3 3a5 5 0 0 0 7.07 7.07l1.71-1.71"></path>
                     </svg>
                 </button>
-                <button id="btn-code" title="Inline Code (Ctrl+`)">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-code" title="Inline Code (Ctrl+`)" aria-label="Insert inline code">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <polyline points="16 18 22 12 16 6"></polyline>
                         <polyline points="8 6 2 12 8 18"></polyline>
                     </svg>
                 </button>
-                <button id="btn-code-block" title="Code Block">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-code-block" title="Code Block" aria-label="Insert code block">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <rect x="2" y="6" width="20" height="12" rx="2"></rect>
                         <path d="m10 10-2 2 2 2"></path>
                         <path d="m14 10 2 2-2 2"></path>
                     </svg>
                 </button>
-                <button id="btn-table" title="Insert Table">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-table" title="Insert Table" aria-label="Insert table">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <rect x="3" y="3" width="18" height="18" rx="2" ry="2"></rect>
                         <line x1="3" y1="9" x2="21" y2="9"></line>
                         <line x1="3" y1="15" x2="21" y2="15"></line>
@@ -114,8 +123,8 @@
                         <line x1="15" y1="3" x2="15" y2="21"></line>
                     </svg>
                 </button>
-                <button id="btn-horizontal-rule" title="Horizontal Rule">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                <button id="btn-horizontal-rule" title="Horizontal Rule" aria-label="Insert horizontal rule">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <line x1="3" y1="12" x2="21" y2="12"></line>
                         <line x1="3" y1="6" x2="21" y2="6"></line>
                         <line x1="3" y1="18" x2="21" y2="18"></line>
@@ -126,20 +135,20 @@
             <div class="toolbar-group">
                 <!-- View: Find, Line Numbers, Preview -->
                 <button id="btn-find" title="Find & Replace (Ctrl+F)">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <circle cx="11" cy="11" r="8"></circle>
                         <path d="m21 21-4.35-4.35"></path>
                     </svg>
                 </button>
                 <button id="btn-line-numbers" title="Toggle Line Numbers">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <path d="M3 6h18"></path>
                         <path d="M3 12h18"></path>
                         <path d="M3 18h18"></path>
                     </svg>
                 </button>
                 <button id="btn-preview-toggle" title="Toggle Preview (Ctrl+Shift+P)">
-                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                    <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" aria-hidden="true">
                         <path d="M1 12s4-8 11-8 11 8 11 8-4 8-11 8-11-8-11-8z"></path>
                         <circle cx="12" cy="12" r="3"></circle>
                     </svg>
@@ -152,29 +161,38 @@
         </div>
 
         <!-- Find & Replace Dialog -->
-        <div id="find-dialog" class="find-dialog hidden">
-            <div class="find-controls">
-                <input type="text" id="find-input" placeholder="Find...">
-                <input type="text" id="replace-input" placeholder="Replace...">
-                <button id="btn-find-prev" title="Previous">↑</button>
-                <button id="btn-find-next" title="Next">↓</button>
-                <button id="btn-replace" title="Replace">Replace</button>
-                <button id="btn-replace-all" title="Replace All">All</button>
-                <button id="btn-find-close" title="Close">×</button>
-            </div>
-            <div class="find-info">
-                <span id="find-count">0 matches</span>
+        <div id="find-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="find-dialog-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content small">
+                <div class="modal-header">
+                    <h3 id="find-dialog-title">Find & Replace</h3>
+                    <button class="modal-close" id="btn-find-close" aria-label="Close">&times;</button>
+                </div>
+                <div class="modal-body">
+                    <div class="find-controls">
+                        <input type="text" id="find-input" placeholder="Find...">
+                        <input type="text" id="replace-input" placeholder="Replace...">
+                        <button id="btn-find-prev" title="Previous">↑</button>
+                        <button id="btn-find-next" title="Next">↓</button>
+                        <button id="btn-replace" title="Replace">Replace</button>
+                        <button id="btn-replace-all" title="Replace All">All</button>
+                    </div>
+                    <div class="find-info">
+                        <span id="find-count">0 matches</span>
+                    </div>
+                </div>
             </div>
         </div>
 
         <!-- Export Options Dialog -->
-        <div id="export-dialog" class="export-dialog hidden">
-            <div class="export-dialog-content">
-                <div class="export-dialog-header">
+        <div id="export-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="export-dialog-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content large">
+                <div class="modal-header">
                     <h3 id="export-dialog-title">Export Options</h3>
-                    <button id="export-dialog-close" title="Close">×</button>
+                    <button class="modal-close" id="export-dialog-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="export-dialog-body">
+                <div class="modal-body">
                     <!-- Simple/Advanced Export Toggle -->
                     <!-- Export Profiles -->
                     <div class="export-section export-profiles">
@@ -323,21 +341,23 @@
                         </div>
                     </div>
                 </div>
-                <div class="export-dialog-footer">
-                    <button id="export-cancel">Cancel</button>
-                    <button id="export-confirm" class="primary">Export</button>
+                <div class="modal-footer">
+                    <button id="export-cancel" class="btn btn-secondary" data-close>Cancel</button>
+                    <button id="export-confirm" class="btn btn-primary">Export</button>
                 </div>
             </div>
         </div>
 
         <!-- Print Preview Dialog -->
-        <div class="export-dialog hidden" id="print-preview-overlay">
-            <div class="export-dialog-content print-preview-dialog">
-                <div class="export-dialog-header">
-                    <h3>Print Preview</h3>
-                    <button id="print-preview-close" title="Close" style="background:none;border:none;color:white;font-size:24px;cursor:pointer;">&times;</button>
+        <div id="print-preview-overlay" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="print-preview-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content full">
+                <div class="modal-header">
+                    <h3 id="print-preview-title">Print Preview</h3>
+                    <button class="modal-close" id="print-preview-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="print-preview-body">
+                <div class="modal-body">
+                    <div class="print-preview-body">
                     <div class="print-preview-sidebar">
                         <div class="print-option-group">
                             <label>Paper Size</label>
@@ -402,6 +422,7 @@
                         <iframe id="print-preview-frame" style="width:100%;height:100%;border:none;background:white;"></iframe>
                     </div>
                 </div>
+                </div>
             </div>
         </div>
 
@@ -414,13 +435,14 @@
         </div>
 
         <!-- Table Generator Dialog -->
-        <div id="table-generator-dialog" class="export-dialog hidden">
-            <div class="export-dialog-content" style="max-width: 500px;">
-                <div class="export-dialog-header">
-                    <h3>📊 Table Generator</h3>
-                    <button id="table-dialog-close" title="Close">×</button>
+        <div id="table-generator-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="table-generator-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content">
+                <div class="modal-header">
+                    <h3 id="table-generator-title">📊 Table Generator</h3>
+                    <button class="modal-close" id="table-dialog-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="export-dialog-body">
+                <div class="modal-body">
                     <div class="export-section">
                         <label for="table-rows">Number of Rows:</label>
                         <input type="number" id="table-rows" min="1" max="50" value="3" style="width: 100px;">
@@ -455,22 +477,23 @@
                         <pre id="table-preview" style="background: #f5f5f5; padding: 10px; border-radius: 4px; font-size: 12px; max-height: 300px; overflow: auto;"></pre>
                     </div>
                 </div>
-                <div class="export-dialog-footer">
-                    <button id="table-generate-preview" class="btn-secondary">Update Preview</button>
-                    <button id="table-insert" class="btn-primary">Insert Table</button>
-                    <button id="table-cancel" class="btn-secondary">Cancel</button>
+                <div class="modal-footer">
+                    <button id="table-generate-preview" class="btn btn-secondary">Update Preview</button>
+                    <button id="table-insert" class="btn btn-primary">Insert Table</button>
+                    <button id="table-cancel" class="btn btn-secondary" data-close>Cancel</button>
                 </div>
             </div>
         </div>
 
         <!-- ASCII Art Generator Dialog -->
-        <div id="ascii-art-dialog" class="export-dialog hidden">
-            <div class="export-dialog-content" style="max-width: 700px;">
-                <div class="export-dialog-header">
-                    <h3>🎨 ASCII Art Generator</h3>
-                    <button id="ascii-dialog-close" title="Close">×</button>
+        <div id="ascii-art-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="ascii-art-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content large">
+                <div class="modal-header">
+                    <h3 id="ascii-art-title">🎨 ASCII Art Generator</h3>
+                    <button class="modal-close" id="ascii-dialog-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="export-dialog-body">
+                <div class="modal-body">
                     <div class="export-section">
                         <label>Mode:</label>
                         <div style="display: flex; gap: 10px; margin-bottom: 10px;">
@@ -566,22 +589,23 @@
                         <pre id="ascii-preview" style="background: #f5f5f5; padding: 15px; border-radius: 4px; font-size: 12px; max-height: 400px; overflow: auto; font-family: 'Courier New', monospace; line-height: 1.2;"></pre>
                     </div>
                 </div>
-                <div class="export-dialog-footer">
-                    <button id="ascii-generate" class="btn-secondary">Generate Preview</button>
-                    <button id="ascii-insert" class="btn-primary">Insert ASCII Art</button>
-                    <button id="ascii-cancel" class="btn-secondary">Cancel</button>
+                <div class="modal-footer">
+                    <button id="ascii-generate" class="btn btn-secondary">Generate Preview</button>
+                    <button id="ascii-insert" class="btn btn-primary">Insert ASCII Art</button>
+                    <button id="ascii-cancel" class="btn btn-secondary" data-close>Cancel</button>
                 </div>
             </div>
         </div>
 
         <!-- Universal File Converter Dialog -->
-        <div id="universal-converter-dialog" class="export-dialog hidden">
-            <div class="export-dialog-content">
-                <div class="export-dialog-header">
-                    <h3>Universal File Converter</h3>
-                    <button id="converter-dialog-close" title="Close">×</button>
+        <div id="universal-converter-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="universal-converter-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content large">
+                <div class="modal-header">
+                    <h3 id="universal-converter-title">Universal File Converter</h3>
+                    <button class="modal-close" id="converter-dialog-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="export-dialog-body">
+                <div class="modal-body">
                     <div class="export-section">
                         <label>Select File to Convert:</label>
                         <div class="folder-input-group">
@@ -795,21 +819,22 @@
                         <small>• Pandoc: Download from <a href="https://pandoc.org/installing.html" target="_blank">pandoc.org</a></small>
                     </div>
                 </div>
-                <div class="export-dialog-footer">
-                    <button id="converter-cancel">Cancel</button>
-                    <button id="converter-convert" class="primary">Convert</button>
+                <div class="modal-footer">
+                    <button id="converter-cancel" class="btn btn-secondary" data-close>Cancel</button>
+                    <button id="converter-convert" class="btn btn-primary">Convert</button>
                 </div>
             </div>
         </div>
 
         <!-- Batch Conversion Dialog -->
-        <div id="batch-dialog" class="batch-dialog hidden">
-            <div class="batch-dialog-content">
-                <div class="batch-dialog-header">
-                    <h3>Batch File Conversion</h3>
-                    <button id="batch-dialog-close" title="Close">×</button>
+        <div id="batch-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="batch-dialog-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content large">
+                <div class="modal-header">
+                    <h3 id="batch-dialog-title">Batch File Conversion</h3>
+                    <button class="modal-close" id="batch-dialog-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="batch-dialog-body">
+                <div class="modal-body">
                     <div class="batch-section">
                         <label>Input Folder:</label>
                         <div class="folder-input-group">
@@ -864,21 +889,22 @@
                         </div>
                     </div>
                 </div>
-                <div class="batch-dialog-footer">
-                    <button id="batch-cancel">Cancel</button>
-                    <button id="batch-start" class="primary" disabled>Start Conversion</button>
+                <div class="modal-footer">
+                    <button id="batch-cancel" class="btn btn-secondary" data-close>Cancel</button>
+                    <button id="batch-start" class="btn btn-primary" disabled>Start Conversion</button>
                 </div>
             </div>
         </div>
 
         <!-- PDF Editor Dialog -->
-        <div id="pdf-editor-dialog" class="export-dialog hidden">
-            <div class="export-dialog-content pdf-editor-content">
-                <div class="export-dialog-header">
+        <div id="pdf-editor-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="pdf-editor-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content full">
+                <div class="modal-header">
                     <h3 id="pdf-editor-title">PDF Editor</h3>
-                    <button id="pdf-editor-dialog-close" title="Close">×</button>
+                    <button class="modal-close" id="pdf-editor-dialog-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="export-dialog-body pdf-editor-body">
+                <div class="modal-body pdf-editor-body">
                     <!-- Merge PDFs Section -->
                     <div id="pdf-merge-section" class="pdf-operation-section hidden">
                         <div class="export-section">
@@ -1249,6 +1275,8 @@
                         </div>
                     </div>
 
+                    <div id="pdf-status-message" class="info-message hidden" aria-live="polite"></div>
+
                     <!-- Progress indicator -->
                     <div id="pdf-progress" class="batch-progress hidden">
                         <div class="progress-bar">
@@ -1259,21 +1287,22 @@
                         </div>
                     </div>
                 </div>
-                <div class="export-dialog-footer">
-                    <button id="pdf-editor-cancel">Cancel</button>
-                    <button id="pdf-editor-process" class="primary">Process</button>
+                <div class="modal-footer">
+                    <button id="pdf-editor-cancel" class="btn btn-secondary" data-close>Cancel</button>
+                    <button id="pdf-editor-process" class="btn btn-primary">Process</button>
                 </div>
             </div>
         </div>
 
         <!-- Header & Footer Configuration Dialog -->
-        <div id="header-footer-dialog" class="export-dialog hidden">
-            <div class="export-dialog-content" style="max-width: 700px;">
-                <div class="export-dialog-header">
-                    <h3>Header & Footer Settings</h3>
-                    <button id="header-footer-close" class="dialog-close" title="Close">×</button>
+        <div id="header-footer-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="header-footer-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content">
+                <div class="modal-header">
+                    <h3 id="header-footer-title">Header & Footer Settings</h3>
+                    <button class="modal-close" id="header-footer-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="export-dialog-body">
+                <div class="modal-body">
                     <div class="hf-enable-section">
                         <label>
                             <input type="checkbox" id="hf-enabled" checked>
@@ -1353,21 +1382,22 @@
                         </div>
                     </div>
                 </div>
-                <div class="export-dialog-footer">
-                    <button id="header-footer-cancel">Cancel</button>
-                    <button id="header-footer-save" class="primary">Save Settings</button>
+                <div class="modal-footer">
+                    <button id="header-footer-cancel" class="btn btn-secondary" data-close>Cancel</button>
+                    <button id="header-footer-save" class="btn btn-primary">Save Settings</button>
                 </div>
             </div>
         </div>
 
         <!-- Dynamic Field Picker Dialog -->
-        <div id="field-picker-dialog" class="export-dialog hidden">
-            <div class="export-dialog-content" style="max-width: 400px;">
-                <div class="export-dialog-header">
-                    <h3>Insert Dynamic Field</h3>
-                    <button id="field-picker-close" class="dialog-close" title="Close">×</button>
+        <div id="field-picker-dialog" class="modal hidden" role="dialog" aria-modal="true" aria-labelledby="field-picker-title">
+            <div class="modal-backdrop" data-close></div>
+            <div class="modal-content small">
+                <div class="modal-header">
+                    <h3 id="field-picker-title">Insert Dynamic Field</h3>
+                    <button class="modal-close" id="field-picker-close" aria-label="Close">&times;</button>
                 </div>
-                <div class="export-dialog-body">
+                <div class="modal-body">
                     <div class="field-picker-list">
                         <button class="field-option" data-field="$PAGE$">Page Number</button>
                         <button class="field-option" data-field="$TOTAL$">Total Pages</button>
@@ -1411,6 +1441,16 @@
                             <line x1="9" y1="21" x2="9" y2="9"/>
                         </svg>
                     </button>
+                    <button class="sidebar-icon" data-panel="outline" title="Outline (Ctrl+Shift+O)">
+                        <svg width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
+                            <line x1="8" y1="6" x2="21" y2="6"/>
+                            <line x1="8" y1="12" x2="21" y2="12"/>
+                            <line x1="8" y1="18" x2="21" y2="18"/>
+                            <line x1="3" y1="6" x2="3.01" y2="6"/>
+                            <line x1="3" y1="12" x2="3.01" y2="12"/>
+                            <line x1="3" y1="18" x2="3.01" y2="18"/>
+                        </svg>
+                    </button>
                 </div>
                 <div class="sidebar-panel" id="sidebar-panel">
                     <div class="sidebar-panel-header">
@@ -1564,6 +1604,7 @@
         </div>
     </div>
 
+    <script src="utils/ModalManager.js"></script>
     <script src="renderer.js"></script>
 </body>
 </html>

src/main.js

@@ -2,8 +2,9 @@ const { app, BrowserWindow, Menu, dialog, ipcMain, shell } = require('electron')
 const path = require('path');
 const fs = require('fs');
 const { exec, execFile, spawn } = require('child_process');
-const { PDFDocument, rgb, degrees, StandardFonts } = require('pdf-lib');
 const WordTemplateExporter = require('./wordTemplateExporter');
+const PDFOperations = require('./main/PDFOperations');
+const GitOperations = require('./main/GitOperations');
 
 // Add MiKTeX to PATH for LaTeX support
 if (process.platform === 'win32') {
@@ -14,13 +15,39 @@ if (process.platform === 'win32') {
   }
 }
 
-// Get the system Pandoc path
+// Returns path to pandoc: bundled binary when packaged, dev bin or system fallback otherwise.
 function getPandocPath() {
-  // Pandoc is expected to be in the system's PATH.
-  // The command will be executed directly. Quoting is handled by exec.
+  if (app.isPackaged) {
+    const ext = process.platform === 'win32' ? '.exe' : '';
+    return path.join(process.resourcesPath, 'bin', `pandoc${ext}`);
+  }
+  // Development: prefer locally-downloaded binary in bin/<platform>/
+  const devBin = path.join(
+    __dirname,
+    '..',
+    'bin',
+    process.platform,
+    process.platform === 'win32' ? 'pandoc.exe' : 'pandoc',
+  );
+  if (fs.existsSync(devBin)) return devBin;
   return 'pandoc';
 }
 
+// Returns path to ffmpeg: asar-unpacked bundled binary when packaged, system fallback otherwise.
+function getFFmpegPath() {
+  try {
+    let ffmpegPath = require('ffmpeg-static');
+    if (app.isPackaged) {
+      // ffmpeg-static is in asarUnpack — rewrite the path to the unpacked location
+      ffmpegPath = ffmpegPath.replace('app.asar' + path.sep, 'app.asar.unpacked' + path.sep);
+    }
+    if (fs.existsSync(ffmpegPath)) return ffmpegPath;
+  } catch (_) {
+    /* ffmpeg-static not available */
+  }
+  return process.platform === 'win32' ? 'ffmpeg' : 'ffmpeg';
+}
+
 // Check if Pandoc is available
 function checkPandocAvailable() {
   return new Promise((resolve) => {
@@ -75,6 +102,110 @@ function createRateLimiter(minIntervalMs = 2000) {
 }
 const conversionLimiter = createRateLimiter(2000);
 
+// ============================================
+// Path Traversal Protection
+// ============================================
+// Define allowed base directories for file operations
+function getAllowedDirectories() {
+  const dirs = [
+    app.getPath('documents'),
+    app.getPath('desktop'),
+    app.getPath('downloads'),
+    app.getPath('home'),
+    process.cwd() // Current working directory
+  ].filter(Boolean); // Remove any undefined paths
+  return dirs;
+}
+
+/**
+ * Validates that a file path is safe and doesn't attempt path traversal
+ * @param {string} filePath - The path to validate
+ * @returns {{ valid: boolean, resolved: string, error?: string }}
+ */
+function validatePath(filePath) {
+  if (!filePath || typeof filePath !== 'string') {
+    return { valid: false, resolved: '', error: 'Invalid path' };
+  }
+
+  // Resolve to absolute path (handles .., ., symlinks)
+  let resolved;
+  try {
+    resolved = path.resolve(filePath);
+  } catch (err) {
+    return { valid: false, resolved: '', error: 'Invalid path format' };
+  }
+
+  // Normalize path separators
+  resolved = path.normalize(resolved);
+
+  // Check for null bytes (path injection)
+  if (resolved.includes('\0')) {
+    return { valid: false, resolved: '', error: 'Null byte in path' };
+  }
+
+  // Check if path exists
+  if (!fs.existsSync(resolved)) {
+    return { valid: false, resolved, error: 'Path does not exist' };
+  }
+
+  return { valid: true, resolved };
+}
+
+/**
+ * Resolves a path for operations where the target may not exist yet.
+ * Validates string shape and blocks obviously sensitive locations.
+ * @param {string} filePath
+ * @returns {{ valid: boolean, resolved: string, error?: string }}
+ */
+function resolveWritablePath(filePath) {
+  if (!filePath || typeof filePath !== 'string') {
+    return { valid: false, resolved: '', error: 'Invalid path' };
+  }
+
+  let resolved;
+  try {
+    resolved = path.normalize(path.resolve(filePath));
+  } catch (err) {
+    return { valid: false, resolved: '', error: 'Invalid path format' };
+  }
+
+  if (resolved.includes('\0')) {
+    return { valid: false, resolved: '', error: 'Null byte in path' };
+  }
+
+  if (!isPathAccessible(resolved)) {
+    return { valid: false, resolved, error: 'Path is not accessible' };
+  }
+
+  return { valid: true, resolved };
+}
+
+/**
+ * Checks if a resolved path is within allowed directories
+ * For an editor app, we allow access to all user-accessible paths
+ * but log any suspicious access attempts
+ * @param {string} resolvedPath - The resolved absolute path
+ * @returns {boolean}
+ */
+function isPathAccessible(resolvedPath) {
+  // Block access to sensitive system directories
+  const blockedPaths = [
+    '/etc/passwd', '/etc/shadow', '/root',
+    'C:\\Windows\\System32', 'C:\\Windows\\System',
+    '/System', '/private/etc'
+  ];
+
+  const normalizedPath = resolvedPath.toLowerCase();
+  for (const blocked of blockedPaths) {
+    if (normalizedPath.startsWith(blocked.toLowerCase())) {
+      console.warn('[SECURITY] Blocked access to sensitive path:', resolvedPath);
+      return false;
+    }
+  }
+
+  return true;
+}
+
 // Convert structured data formats to markdown code blocks
 function convertDataToMarkdown(content, format) {
     switch (format) {
@@ -179,6 +310,41 @@ const store = {
   }
 };
 
+// Plugin settings IPC handlers
+ipcMain.handle('plugin-settings:get', (_event, key) => {
+  return store.get(key);
+});
+ipcMain.handle('plugin-settings:set', (_event, { key, value }) => {
+  store.set(key, value);
+});
+ipcMain.handle('get-app-version', () => app.getVersion());
+
+// ============================================
+// SECURITY: Permission Request Handler
+// ============================================
+// Restrict permissions to only those explicitly needed.
+// Deny: camera, microphone, geolocation, notifications, etc.
+// Allow: clipboard-read, clipboard-write (user expects these)
+app.on('web-contents-created', (event, contents) => {
+  contents.session.setPermissionRequestHandler((webContents, permission, callback) => {
+    const ALLOWED_PERMISSIONS = [
+      'clipboard-read',
+      'clipboard-write'
+    ];
+
+    if (ALLOWED_PERMISSIONS.includes(permission)) {
+      callback(true);
+    } else {
+      // Deny all other permissions (camera, microphone, geolocation, etc.)
+      console.warn(`[Security] Blocked permission request: ${permission}`);
+      callback(false);
+    }
+  });
+
+  // Disable file download dialogs for security
+  // contents.session.setDownloadPath(userDownloadsPath);
+});
+
 let mainWindow;
 let currentFile = null; // This will now represent the active tab's file
 let pandocAvailable = null; // Cache pandoc availability check
@@ -925,7 +1091,7 @@ function showAboutDialog() {
 <body>
   <img src="${iconBase64}" class="logo" alt="MarkdownConverter">
   <h1>MarkdownConverter</h1>
-  <div class="version">Version 4.0.0</div>
+  <div class="version">Version ${app.getVersion()}</div>
 
   <div class="company">
     <span>by</span>
@@ -1729,9 +1895,12 @@ function checkConverterAvailable(tool) {
       case 'imagemagick':
         toolName = isWin ? 'magick' : 'convert';
         break;
-      case 'ffmpeg':
-        toolName = 'ffmpeg';
-        break;
+      case 'ffmpeg': {
+        // ffmpeg-static is always bundled — check it directly
+        const ffmpegBin = getFFmpegPath();
+        resolve(fs.existsSync(ffmpegBin) || ffmpegBin === 'ffmpeg');
+        return;
+      }
       default:
         resolve(false);
         return;
@@ -1958,8 +2127,8 @@ function convertWithImageMagick(inputFile, outputPath) {
 // FFmpeg conversion - returns {command, args} for execFile
 function convertWithFFmpeg(inputFile, outputPath) {
   return {
-    command: 'ffmpeg',
-    args: ['-i', inputFile, outputPath, '-y']
+    command: getFFmpegPath(),
+    args: ['-i', inputFile, outputPath, '-y'],
   };
 }
 
@@ -2718,9 +2887,13 @@ ipcMain.on('save-file', (event, { path, content }) => {
   currentFile = path;
 });
 
-ipcMain.on('save-current-file', (event, content) => {
-  if (currentFile) {
-    fs.writeFileSync(currentFile, content, 'utf-8');
+ipcMain.on('save-current-file', (event, payload) => {
+  const content = typeof payload === 'string' ? payload : payload?.content;
+  const targetFile = typeof payload === 'string' ? currentFile : payload?.filePath || currentFile;
+
+  if (targetFile) {
+    fs.writeFileSync(targetFile, content, 'utf-8');
+    currentFile = targetFile;
   } else {
     saveAsFile();
   }
@@ -3611,433 +3784,9 @@ function openFileFromPath(filePath) {
 }
 
 // ========================================
-// PDF EDITOR OPERATIONS (using pdf-lib)
+// PDF OPERATIONS — delegates to main/PDFOperations.js
 // ========================================
 
-// Helper function to parse page ranges (e.g., "1-5, 7, 9-12")
-function parsePageRanges(rangeString, totalPages) {
-  const pages = [];
-  const ranges = rangeString.split(',').map(r => r.trim());
-
-  for (const range of ranges) {
-    if (range.includes('-')) {
-      const [start, end] = range.split('-').map(n => parseInt(n.trim()));
-      for (let i = start; i <= end && i <= totalPages; i++) {
-        if (i > 0 && !pages.includes(i - 1)) { // Convert to 0-indexed
-          pages.push(i - 1);
-        }
-      }
-    } else {
-      const page = parseInt(range);
-      if (page > 0 && page <= totalPages && !pages.includes(page - 1)) {
-        pages.push(page - 1);
-      }
-    }
-  }
-
-  return pages.sort((a, b) => a - b);
-}
-
-// Helper function to convert hex color to RGB
-function hexToRgb(hex) {
-  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
-  return result ? {
-    r: parseInt(result[1], 16) / 255,
-    g: parseInt(result[2], 16) / 255,
-    b: parseInt(result[3], 16) / 255
-  } : { r: 0, g: 0, b: 0 };
-}
-
-// PDF Merge Operation
-async function pdfMerge(data) {
-  try {
-    const mergedPdf = await PDFDocument.create();
-
-    for (const filePath of data.inputFiles) {
-      const pdfBytes = fs.readFileSync(filePath);
-      const pdf = await PDFDocument.load(pdfBytes);
-      const copiedPages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
-      copiedPages.forEach(page => mergedPdf.addPage(page));
-    }
-
-    const pdfBytes = await mergedPdf.save();
-    fs.writeFileSync(data.outputPath, pdfBytes);
-
-    return { success: true, message: `Successfully merged ${data.inputFiles.length} PDFs` };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Split Operation
-async function pdfSplit(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    let splits = [];
-
-    if (data.splitMode === 'pages') {
-      // Split by page ranges
-      const ranges = data.pageRanges.split(',').map(r => r.trim());
-      for (let i = 0; i < ranges.length; i++) {
-        const range = ranges[i];
-        let pages = [];
-
-        if (range.includes('-')) {
-          const [start, end] = range.split('-').map(n => parseInt(n.trim()));
-          for (let p = start; p <= end && p <= totalPages; p++) {
-            pages.push(p - 1);
-          }
-        } else {
-          const page = parseInt(range);
-          if (page > 0 && page <= totalPages) {
-            pages.push(page - 1);
-          }
-        }
-
-        if (pages.length > 0) {
-          splits.push({ pages, name: `part_${i + 1}` });
-        }
-      }
-    } else if (data.splitMode === 'interval') {
-      // Split every N pages
-      const interval = data.interval;
-      for (let i = 0; i < totalPages; i += interval) {
-        const pages = [];
-        for (let j = i; j < i + interval && j < totalPages; j++) {
-          pages.push(j);
-        }
-        splits.push({ pages, name: `part_${Math.floor(i / interval) + 1}` });
-      }
-    } else if (data.splitMode === 'size') {
-      // Split by size (approximate - we'll split evenly)
-      // This is complex, so we'll do a simple even split for now
-      const maxSize = data.maxSize * 1024 * 1024; // Convert MB to bytes
-      // For simplicity, split into fixed page chunks
-      const chunkSize = Math.max(1, Math.floor(totalPages / 5)); // Split into ~5 parts
-      for (let i = 0; i < totalPages; i += chunkSize) {
-        const pages = [];
-        for (let j = i; j < i + chunkSize && j < totalPages; j++) {
-          pages.push(j);
-        }
-        splits.push({ pages, name: `part_${Math.floor(i / chunkSize) + 1}` });
-      }
-    }
-
-    // Create split PDFs
-    const baseName = path.basename(data.inputPath, '.pdf');
-    for (const split of splits) {
-      const newPdf = await PDFDocument.create();
-      const copiedPages = await newPdf.copyPages(pdf, split.pages);
-      copiedPages.forEach(page => newPdf.addPage(page));
-
-      const outputPath = path.join(data.outputFolder, `${baseName}_${split.name}.pdf`);
-      const newPdfBytes = await newPdf.save();
-      fs.writeFileSync(outputPath, newPdfBytes);
-    }
-
-    return { success: true, message: `Successfully split PDF into ${splits.length} files` };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Compress Operation
-async function pdfCompress(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-
-    // pdf-lib doesn't have built-in compression, but we can save with default compression
-    // For actual compression, we would need additional libraries like Ghostscript
-    // For now, we'll save with standard options which provides some compression
-    const compressedPdfBytes = await pdf.save({
-      useObjectStreams: true,
-      addDefaultPage: false,
-      objectsPerTick: 50
-    });
-
-    fs.writeFileSync(data.outputPath, compressedPdfBytes);
-
-    const originalSize = fs.statSync(data.inputPath).size;
-    const compressedSize = fs.statSync(data.outputPath).size;
-    const savings = ((originalSize - compressedSize) / originalSize * 100).toFixed(1);
-
-    return {
-      success: true,
-      message: `PDF compressed. Size reduced by ${savings}% (${(originalSize / 1024).toFixed(1)}KB → ${(compressedSize / 1024).toFixed(1)}KB)`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Rotate Pages Operation
-async function pdfRotate(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    let pagesToRotate = [];
-    if (data.pages && data.pages.trim()) {
-      pagesToRotate = parsePageRanges(data.pages, totalPages);
-    } else {
-      // Rotate all pages
-      pagesToRotate = Array.from({ length: totalPages }, (_, i) => i);
-    }
-
-    pagesToRotate.forEach(pageIndex => {
-      const page = pdf.getPage(pageIndex);
-      page.setRotation(degrees(data.angle));
-    });
-
-    const rotatedPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, rotatedPdfBytes);
-
-    return {
-      success: true,
-      message: `Successfully rotated ${pagesToRotate.length} page(s) by ${data.angle}°`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Delete Pages Operation
-async function pdfDeletePages(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    const pagesToDelete = parsePageRanges(data.pages, totalPages);
-
-    // Remove pages in reverse order to maintain indices
-    pagesToDelete.sort((a, b) => b - a).forEach(pageIndex => {
-      pdf.removePage(pageIndex);
-    });
-
-    const newPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, newPdfBytes);
-
-    return {
-      success: true,
-      message: `Successfully deleted ${pagesToDelete.length} page(s). New PDF has ${totalPages - pagesToDelete.length} pages`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Reorder Pages Operation
-async function pdfReorder(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    // Parse new page order
-    const newOrder = data.newOrder.split(',').map(n => parseInt(n.trim()) - 1); // Convert to 0-indexed
-
-    // Validate new order
-    if (newOrder.length !== totalPages) {
-      return { success: false, error: `New order must include all ${totalPages} pages` };
-    }
-
-    const newPdf = await PDFDocument.create();
-    const copiedPages = await newPdf.copyPages(pdf, newOrder);
-    copiedPages.forEach(page => newPdf.addPage(page));
-
-    const reorderedPdfBytes = await newPdf.save();
-    fs.writeFileSync(data.outputPath, reorderedPdfBytes);
-
-    return { success: true, message: 'Successfully reordered PDF pages' };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Watermark Operation
-async function pdfWatermark(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const totalPages = pdf.getPageCount();
-
-    // Determine which pages to watermark
-    let pagesToWatermark = [];
-    if (data.pages === 'all') {
-      pagesToWatermark = Array.from({ length: totalPages }, (_, i) => i);
-    } else if (data.pages === 'custom' && data.customPages) {
-      pagesToWatermark = parsePageRanges(data.customPages, totalPages);
-    }
-
-    const font = await pdf.embedFont(StandardFonts.Helvetica);
-    const color = hexToRgb(data.color);
-
-    for (const pageIndex of pagesToWatermark) {
-      const page = pdf.getPage(pageIndex);
-      const { width, height } = page.getSize();
-
-      let x, y, rotation = 0;
-
-      // Calculate position based on selected position
-      switch (data.position) {
-        case 'center':
-          x = width / 2;
-          y = height / 2;
-          break;
-        case 'diagonal':
-          x = width / 2;
-          y = height / 2;
-          rotation = 45;
-          break;
-        case 'top-left':
-          x = 50;
-          y = height - 50;
-          break;
-        case 'top-center':
-          x = width / 2;
-          y = height - 50;
-          break;
-        case 'top-right':
-          x = width - 50;
-          y = height - 50;
-          break;
-        case 'bottom-left':
-          x = 50;
-          y = 50;
-          break;
-        case 'bottom-center':
-          x = width / 2;
-          y = 50;
-          break;
-        case 'bottom-right':
-          x = width - 50;
-          y = 50;
-          break;
-        default:
-          x = width / 2;
-          y = height / 2;
-      }
-
-      page.drawText(data.text, {
-        x,
-        y,
-        size: data.fontSize,
-        font,
-        color: rgb(color.r, color.g, color.b),
-        opacity: data.opacity,
-        rotate: degrees(rotation)
-      });
-    }
-
-    const watermarkedPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, watermarkedPdfBytes);
-
-    return {
-      success: true,
-      message: `Successfully added watermark to ${pagesToWatermark.length} page(s)`
-    };
-  } catch (error) {
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Encrypt (Password Protection) Operation
-async function pdfEncrypt(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes);
-
-    // pdf-lib has limited encryption support in v1.17.1
-    // We'll save with password (basic encryption)
-    const encryptedPdfBytes = await pdf.save({
-      userPassword: data.userPassword,
-      ownerPassword: data.ownerPassword || data.userPassword,
-      permissions: {
-        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
-        modifying: data.permissions.modifying,
-        copying: data.permissions.copying,
-        annotating: data.permissions.annotating,
-        fillingForms: data.permissions.fillingForms,
-        contentAccessibility: data.permissions.contentAccessibility,
-        documentAssembly: data.permissions.documentAssembly
-      }
-    });
-
-    fs.writeFileSync(data.outputPath, encryptedPdfBytes);
-
-    return { success: true, message: 'Successfully added password protection to PDF' };
-  } catch (error) {
-    // If pdf-lib doesn't support encryption in this version, provide a helpful error
-    if (error.message.includes('encrypt') || error.message.includes('password')) {
-      return {
-        success: false,
-        error: 'PDF encryption requires pdf-lib with encryption support. This feature may not be available in the current version.'
-      };
-    }
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Decrypt (Remove Password) Operation
-async function pdfDecrypt(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const pdf = await PDFDocument.load(pdfBytes, { password: data.password });
-
-    // Save without password
-    const decryptedPdfBytes = await pdf.save();
-    fs.writeFileSync(data.outputPath, decryptedPdfBytes);
-
-    return { success: true, message: 'Successfully removed password protection from PDF' };
-  } catch (error) {
-    if (error.message.includes('password') || error.message.includes('encrypted')) {
-      return { success: false, error: 'Incorrect password or PDF is not encrypted' };
-    }
-    return { success: false, error: error.message };
-  }
-}
-
-// PDF Permissions Operation
-async function pdfSetPermissions(data) {
-  try {
-    const pdfBytes = fs.readFileSync(data.inputPath);
-    const loadOptions = data.currentPassword ? { password: data.currentPassword } : {};
-    const pdf = await PDFDocument.load(pdfBytes, loadOptions);
-
-    const newPdfBytes = await pdf.save({
-      ownerPassword: data.ownerPassword,
-      permissions: {
-        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
-        modifying: data.permissions.modifying,
-        copying: data.permissions.copying,
-        annotating: data.permissions.annotating,
-        fillingForms: data.permissions.fillingForms,
-        contentAccessibility: data.permissions.contentAccessibility,
-        documentAssembly: data.permissions.documentAssembly
-      }
-    });
-
-    fs.writeFileSync(data.outputPath, newPdfBytes);
-
-    return { success: true, message: 'Successfully updated PDF permissions' };
-  } catch (error) {
-    if (error.message.includes('encrypt') || error.message.includes('permission')) {
-      return {
-        success: false,
-        error: 'PDF permissions require pdf-lib with encryption support. This feature may not be available in the current version.'
-      };
-    }
-    return { success: false, error: error.message };
-  }
-}
-
-// IPC Handler for PDF Operations
 ipcMain.on('process-pdf-operation', async (event, data) => {
   try {
     mainWindow.webContents.send('pdf-operation-progress', {
@@ -4045,43 +3794,7 @@ ipcMain.on('process-pdf-operation', async (event, data) => {
       progress: 10
     });
 
-    let result;
-
-    switch (data.operation) {
-      case 'merge':
-        result = await pdfMerge(data);
-        break;
-      case 'split':
-        result = await pdfSplit(data);
-        break;
-      case 'compress':
-        result = await pdfCompress(data);
-        break;
-      case 'rotate':
-        result = await pdfRotate(data);
-        break;
-      case 'delete':
-        result = await pdfDeletePages(data);
-        break;
-      case 'reorder':
-        result = await pdfReorder(data);
-        break;
-      case 'watermark':
-        result = await pdfWatermark(data);
-        break;
-      case 'encrypt':
-        result = await pdfEncrypt(data);
-        break;
-      case 'decrypt':
-        result = await pdfDecrypt(data);
-        break;
-      case 'permissions':
-        result = await pdfSetPermissions(data);
-        break;
-      default:
-        result = { success: false, error: `Unknown operation: ${data.operation}` };
-    }
-
+    const result = await PDFOperations.executeOperation(data.operation, data);
     mainWindow.webContents.send('pdf-operation-complete', result);
   } catch (error) {
     mainWindow.webContents.send('pdf-operation-complete', {
@@ -4091,12 +3804,9 @@ ipcMain.on('process-pdf-operation', async (event, data) => {
   }
 });
 
-// IPC Handler for getting PDF page count
 ipcMain.on('get-pdf-page-count', async (event, filePath) => {
   try {
-    const pdfBytes = fs.readFileSync(filePath);
-    const pdf = await PDFDocument.load(pdfBytes);
-    const count = pdf.getPageCount();
+    const count = await PDFOperations.getPageCount(filePath);
     event.reply('pdf-page-count', { count });
   } catch (error) {
     event.reply('pdf-page-count', { error: error.message });
@@ -4247,7 +3957,19 @@ ipcMain.handle('list-directory', async (event, dirPath) => {
       if (result.canceled || !result.filePaths[0]) return null;
       dirPath = result.filePaths[0];
     }
-    const entries = fs.readdirSync(dirPath, { withFileTypes: true })
+
+    // Validate path to prevent traversal attacks
+    const validation = validatePath(dirPath);
+    if (!validation.valid) {
+      console.error('[SECURITY] Invalid directory path:', validation.error);
+      return null;
+    }
+
+    if (!isPathAccessible(validation.resolved)) {
+      return null;
+    }
+
+    const entries = fs.readdirSync(validation.resolved, { withFileTypes: true })
       .filter(e => !e.name.startsWith('.'))
       .sort((a, b) => {
         if (a.isDirectory() && !b.isDirectory()) return -1;
@@ -4257,24 +3979,133 @@ ipcMain.handle('list-directory', async (event, dirPath) => {
       .map(e => ({
         name: e.name,
         isDirectory: e.isDirectory(),
-        path: path.join(dirPath, e.name)
+        size: e.isDirectory() ? 0 : fs.statSync(path.join(validation.resolved, e.name)).size,
+        modified: fs.statSync(path.join(validation.resolved, e.name)).mtimeMs,
+        path: path.join(validation.resolved, e.name)
       }));
-    return { path: dirPath, entries };
+    return { path: validation.resolved, entries };
   } catch (err) {
     console.error('list-directory error:', err);
     return null;
   }
 });
 
+ipcMain.handle('read-file', async (event, filePath) => {
+  const validation = validatePath(filePath);
+  if (!validation.valid || !isPathAccessible(validation.resolved)) {
+    throw new Error(validation.error || 'Invalid file path');
+  }
+
+  return fs.readFileSync(validation.resolved, 'utf-8');
+});
+
+ipcMain.handle('write-file', async (event, payload) => {
+  const validation = resolveWritablePath(payload?.path);
+  if (!validation.valid) {
+    throw new Error(validation.error || 'Invalid file path');
+  }
+
+  fs.mkdirSync(path.dirname(validation.resolved), { recursive: true });
+  fs.writeFileSync(validation.resolved, payload?.content ?? '', 'utf-8');
+  return { path: validation.resolved };
+});
+
+ipcMain.handle('delete-file', async (event, filePath) => {
+  const validation = validatePath(filePath);
+  if (!validation.valid || !isPathAccessible(validation.resolved)) {
+    throw new Error(validation.error || 'Invalid file path');
+  }
+
+  fs.rmSync(validation.resolved, { recursive: true, force: false });
+  return true;
+});
+
+ipcMain.handle('ensure-directory', async (event, dirPath) => {
+  const validation = resolveWritablePath(dirPath);
+  if (!validation.valid) {
+    throw new Error(validation.error || 'Invalid directory path');
+  }
+
+  fs.mkdirSync(validation.resolved, { recursive: true });
+  return validation.resolved;
+});
+
+ipcMain.handle('path-exists', async (event, filePath) => {
+  const validation = resolveWritablePath(filePath);
+  return validation.valid ? fs.existsSync(validation.resolved) : false;
+});
+
+ipcMain.handle('is-directory', async (event, filePath) => {
+  const validation = validatePath(filePath);
+  if (!validation.valid || !isPathAccessible(validation.resolved)) {
+    return false;
+  }
+
+  return fs.statSync(validation.resolved).isDirectory();
+});
+
+ipcMain.handle('copy-path', async (event, payload) => {
+  const sourceValidation = validatePath(payload?.source);
+  const destinationValidation = resolveWritablePath(payload?.destination);
+
+  if (!sourceValidation.valid || !isPathAccessible(sourceValidation.resolved)) {
+    throw new Error(sourceValidation.error || 'Invalid source path');
+  }
+  if (!destinationValidation.valid) {
+    throw new Error(destinationValidation.error || 'Invalid destination path');
+  }
+
+  fs.mkdirSync(path.dirname(destinationValidation.resolved), { recursive: true });
+  fs.cpSync(sourceValidation.resolved, destinationValidation.resolved, { recursive: true });
+  return { source: sourceValidation.resolved, destination: destinationValidation.resolved };
+});
+
+ipcMain.handle('move-path', async (event, payload) => {
+  const sourceValidation = validatePath(payload?.source);
+  const destinationValidation = resolveWritablePath(payload?.destination);
+
+  if (!sourceValidation.valid || !isPathAccessible(sourceValidation.resolved)) {
+    throw new Error(sourceValidation.error || 'Invalid source path');
+  }
+  if (!destinationValidation.valid) {
+    throw new Error(destinationValidation.error || 'Invalid destination path');
+  }
+
+  fs.mkdirSync(path.dirname(destinationValidation.resolved), { recursive: true });
+
+  try {
+    fs.renameSync(sourceValidation.resolved, destinationValidation.resolved);
+  } catch (error) {
+    if (error.code !== 'EXDEV') {
+      throw error;
+    }
+
+    fs.cpSync(sourceValidation.resolved, destinationValidation.resolved, { recursive: true });
+    fs.rmSync(sourceValidation.resolved, { recursive: true, force: false });
+  }
+
+  return { source: sourceValidation.resolved, destination: destinationValidation.resolved };
+});
+
 // Open a file by path (from explorer panel)
 ipcMain.on('open-file-path', (event, filePath) => {
   try {
-    if (!fs.existsSync(filePath)) return;
-    const stat = fs.statSync(filePath);
+    // Validate path to prevent traversal attacks
+    const validation = validatePath(filePath);
+    if (!validation.valid) {
+      console.error('[SECURITY] Invalid file path:', validation.error);
+      return;
+    }
+
+    if (!isPathAccessible(validation.resolved)) {
+      return;
+    }
+
+    const stat = fs.statSync(validation.resolved);
     if (stat.size > MAX_FILE_SIZE) return;
-    currentFile = filePath;
-    const content = fs.readFileSync(filePath, 'utf-8');
-    mainWindow.webContents.send('file-opened', { path: filePath, content });
+    currentFile = validation.resolved;
+    const content = fs.readFileSync(validation.resolved, 'utf-8');
+    mainWindow.webContents.send('file-opened', { path: validation.resolved, content });
   } catch (err) {
     console.error('open-file-path error:', err);
   }
@@ -4283,49 +4114,24 @@ ipcMain.on('open-file-path', (event, filePath) => {
 // ============================================
 // Git IPC Handlers
 // ============================================
-const simpleGit = require('simple-git');
-
-function getGitRepo() {
-  // Use the directory of the current file, or the app's working directory
-  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
-  return simpleGit(dir);
-}
-
 ipcMain.handle('git-status', async () => {
-  try {
-    const git = getGitRepo();
-    return await git.status();
-  } catch (err) {
-    return { error: 'Not a git repository' };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.getStatus(dir);
 });
 
 ipcMain.handle('git-stage', async (event, { files }) => {
-  try {
-    const git = getGitRepo();
-    await git.add(files);
-    return await git.status();
-  } catch (err) {
-    return { error: err.message };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.stage(dir, files);
 });
 
 ipcMain.handle('git-commit', async (event, { message }) => {
-  try {
-    const git = getGitRepo();
-    return await git.commit(message);
-  } catch (err) {
-    return { error: err.message };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.commit(dir, message);
 });
 
 ipcMain.handle('git-log', async () => {
-  try {
-    const git = getGitRepo();
-    return await git.log({ maxCount: 20 });
-  } catch (err) {
-    return { error: err.message };
-  }
+  const dir = currentFile ? path.dirname(currentFile) : process.cwd();
+  return GitOperations.log(dir);
 });
 
 // ============================================

src/main/GitOperations.js

@@ -0,0 +1,44 @@
+const simpleGit = require('simple-git');
+
+function getGitInstance(dir) {
+  return simpleGit(dir);
+}
+
+async function getStatus(dir) {
+  try {
+    const git = getGitInstance(dir);
+    return await git.status();
+  } catch (err) {
+    return { error: 'Not a git repository' };
+  }
+}
+
+async function stage(dir, files) {
+  try {
+    const git = getGitInstance(dir);
+    await git.add(files);
+    return await git.status();
+  } catch (err) {
+    return { error: err.message };
+  }
+}
+
+async function commit(dir, message) {
+  try {
+    const git = getGitInstance(dir);
+    return await git.commit(message);
+  } catch (err) {
+    return { error: err.message };
+  }
+}
+
+async function log(dir, maxCount = 20) {
+  try {
+    const git = getGitInstance(dir);
+    return await git.log({ maxCount });
+  } catch (err) {
+    return { error: err.message };
+  }
+}
+
+module.exports = { getStatus, stage, commit, log };

src/main/PDFOperations.js

@@ -0,0 +1,433 @@
+const fs = require('fs');
+const path = require('path');
+const { PDFDocument, rgb, degrees, StandardFonts } = require('pdf-lib');
+
+function parsePageRanges(rangeString, totalPages) {
+  const pages = [];
+  const ranges = rangeString.split(',').map(r => r.trim());
+
+  for (const range of ranges) {
+    if (range.includes('-')) {
+      const [start, end] = range.split('-').map(n => parseInt(n.trim()));
+      for (let i = start; i <= end && i <= totalPages; i++) {
+        if (i > 0 && !pages.includes(i - 1)) {
+          pages.push(i - 1);
+        }
+      }
+    } else {
+      const page = parseInt(range);
+      if (page > 0 && page <= totalPages && !pages.includes(page - 1)) {
+        pages.push(page - 1);
+      }
+    }
+  }
+
+  return pages.sort((a, b) => a - b);
+}
+
+function hexToRgb(hex) {
+  const result = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.exec(hex);
+  return result ? {
+    r: parseInt(result[1], 16) / 255,
+    g: parseInt(result[2], 16) / 255,
+    b: parseInt(result[3], 16) / 255
+  } : { r: 0, g: 0, b: 0 };
+}
+
+async function pdfMerge(data) {
+  try {
+    const mergedPdf = await PDFDocument.create();
+
+    for (const filePath of data.inputFiles) {
+      const pdfBytes = fs.readFileSync(filePath);
+      const pdf = await PDFDocument.load(pdfBytes);
+      const copiedPages = await mergedPdf.copyPages(pdf, pdf.getPageIndices());
+      copiedPages.forEach(page => mergedPdf.addPage(page));
+    }
+
+    const pdfBytes = await mergedPdf.save();
+    fs.writeFileSync(data.outputPath, pdfBytes);
+
+    return { success: true, message: `Successfully merged ${data.inputFiles.length} PDFs` };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfSplit(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    let splits = [];
+
+    if (data.splitMode === 'pages') {
+      const ranges = data.pageRanges.split(',').map(r => r.trim());
+      for (let i = 0; i < ranges.length; i++) {
+        const range = ranges[i];
+        let pages = [];
+
+        if (range.includes('-')) {
+          const [start, end] = range.split('-').map(n => parseInt(n.trim()));
+          for (let p = start; p <= end && p <= totalPages; p++) {
+            pages.push(p - 1);
+          }
+        } else {
+          const page = parseInt(range);
+          if (page > 0 && page <= totalPages) {
+            pages.push(page - 1);
+          }
+        }
+
+        if (pages.length > 0) {
+          splits.push({ pages, name: `part_${i + 1}` });
+        }
+      }
+    } else if (data.splitMode === 'interval') {
+      const interval = data.interval;
+      for (let i = 0; i < totalPages; i += interval) {
+        const pages = [];
+        for (let j = i; j < i + interval && j < totalPages; j++) {
+          pages.push(j);
+        }
+        splits.push({ pages, name: `part_${Math.floor(i / interval) + 1}` });
+      }
+    } else if (data.splitMode === 'size') {
+      const chunkSize = Math.max(1, Math.floor(totalPages / 5));
+      for (let i = 0; i < totalPages; i += chunkSize) {
+        const pages = [];
+        for (let j = i; j < i + chunkSize && j < totalPages; j++) {
+          pages.push(j);
+        }
+        splits.push({ pages, name: `part_${Math.floor(i / chunkSize) + 1}` });
+      }
+    }
+
+    const baseName = path.basename(data.inputPath, '.pdf');
+    for (const split of splits) {
+      const newPdf = await PDFDocument.create();
+      const copiedPages = await newPdf.copyPages(pdf, split.pages);
+      copiedPages.forEach(page => newPdf.addPage(page));
+
+      const outputPath = path.join(data.outputFolder, `${baseName}_${split.name}.pdf`);
+      const newPdfBytes = await newPdf.save();
+      fs.writeFileSync(outputPath, newPdfBytes);
+    }
+
+    return { success: true, message: `Successfully split PDF into ${splits.length} files` };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfCompress(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+
+    const compressedPdfBytes = await pdf.save({
+      useObjectStreams: true,
+      addDefaultPage: false,
+      objectsPerTick: 50
+    });
+
+    fs.writeFileSync(data.outputPath, compressedPdfBytes);
+
+    const originalSize = fs.statSync(data.inputPath).size;
+    const compressedSize = fs.statSync(data.outputPath).size;
+    const savings = ((originalSize - compressedSize) / originalSize * 100).toFixed(1);
+
+    return {
+      success: true,
+      message: `PDF compressed. Size reduced by ${savings}% (${(originalSize / 1024).toFixed(1)}KB → ${(compressedSize / 1024).toFixed(1)}KB)`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfRotate(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    let pagesToRotate = [];
+    if (data.pages && data.pages.trim()) {
+      pagesToRotate = parsePageRanges(data.pages, totalPages);
+    } else {
+      pagesToRotate = Array.from({ length: totalPages }, (_, i) => i);
+    }
+
+    pagesToRotate.forEach(pageIndex => {
+      const page = pdf.getPage(pageIndex);
+      page.setRotation(degrees(data.angle));
+    });
+
+    const rotatedPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, rotatedPdfBytes);
+
+    return {
+      success: true,
+      message: `Successfully rotated ${pagesToRotate.length} page(s) by ${data.angle}\u00B0`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfDeletePages(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    const pagesToDelete = parsePageRanges(data.pages, totalPages);
+
+    pagesToDelete.sort((a, b) => b - a).forEach(pageIndex => {
+      pdf.removePage(pageIndex);
+    });
+
+    const newPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, newPdfBytes);
+
+    return {
+      success: true,
+      message: `Successfully deleted ${pagesToDelete.length} page(s). New PDF has ${totalPages - pagesToDelete.length} pages`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfReorder(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    const newOrder = data.newOrder.split(',').map(n => parseInt(n.trim()) - 1);
+
+    if (newOrder.length !== totalPages) {
+      return { success: false, error: `New order must include all ${totalPages} pages` };
+    }
+
+    const newPdf = await PDFDocument.create();
+    const copiedPages = await newPdf.copyPages(pdf, newOrder);
+    copiedPages.forEach(page => newPdf.addPage(page));
+
+    const reorderedPdfBytes = await newPdf.save();
+    fs.writeFileSync(data.outputPath, reorderedPdfBytes);
+
+    return { success: true, message: 'Successfully reordered PDF pages' };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfWatermark(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+    const totalPages = pdf.getPageCount();
+
+    let pagesToWatermark = [];
+    if (data.pages === 'all') {
+      pagesToWatermark = Array.from({ length: totalPages }, (_, i) => i);
+    } else if (data.pages === 'custom' && data.customPages) {
+      pagesToWatermark = parsePageRanges(data.customPages, totalPages);
+    }
+
+    const font = await pdf.embedFont(StandardFonts.Helvetica);
+    const color = hexToRgb(data.color);
+
+    for (const pageIndex of pagesToWatermark) {
+      const page = pdf.getPage(pageIndex);
+      const { width, height } = page.getSize();
+
+      let x, y, rotation = 0;
+
+      switch (data.position) {
+        case 'center':
+          x = width / 2;
+          y = height / 2;
+          break;
+        case 'diagonal':
+          x = width / 2;
+          y = height / 2;
+          rotation = 45;
+          break;
+        case 'top-left':
+          x = 50;
+          y = height - 50;
+          break;
+        case 'top-center':
+          x = width / 2;
+          y = height - 50;
+          break;
+        case 'top-right':
+          x = width - 50;
+          y = height - 50;
+          break;
+        case 'bottom-left':
+          x = 50;
+          y = 50;
+          break;
+        case 'bottom-center':
+          x = width / 2;
+          y = 50;
+          break;
+        case 'bottom-right':
+          x = width - 50;
+          y = 50;
+          break;
+        default:
+          x = width / 2;
+          y = height / 2;
+      }
+
+      page.drawText(data.text, {
+        x,
+        y,
+        size: data.fontSize,
+        font,
+        color: rgb(color.r, color.g, color.b),
+        opacity: data.opacity,
+        rotate: degrees(rotation)
+      });
+    }
+
+    const watermarkedPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, watermarkedPdfBytes);
+
+    return {
+      success: true,
+      message: `Successfully added watermark to ${pagesToWatermark.length} page(s)`
+    };
+  } catch (error) {
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfEncrypt(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes);
+
+    const encryptedPdfBytes = await pdf.save({
+      userPassword: data.userPassword,
+      ownerPassword: data.ownerPassword || data.userPassword,
+      permissions: {
+        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
+        modifying: data.permissions.modifying,
+        copying: data.permissions.copying,
+        annotating: data.permissions.annotating,
+        fillingForms: data.permissions.fillingForms,
+        contentAccessibility: data.permissions.contentAccessibility,
+        documentAssembly: data.permissions.documentAssembly
+      }
+    });
+
+    fs.writeFileSync(data.outputPath, encryptedPdfBytes);
+
+    return { success: true, message: 'Successfully added password protection to PDF' };
+  } catch (error) {
+    if (error.message.includes('encrypt') || error.message.includes('password')) {
+      return {
+        success: false,
+        error: 'PDF encryption requires pdf-lib with encryption support. This feature may not be available in the current version.'
+      };
+    }
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfDecrypt(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const pdf = await PDFDocument.load(pdfBytes, { password: data.password });
+
+    const decryptedPdfBytes = await pdf.save();
+    fs.writeFileSync(data.outputPath, decryptedPdfBytes);
+
+    return { success: true, message: 'Successfully removed password protection from PDF' };
+  } catch (error) {
+    if (error.message.includes('password') || error.message.includes('encrypted')) {
+      return { success: false, error: 'Incorrect password or PDF is not encrypted' };
+    }
+    return { success: false, error: error.message };
+  }
+}
+
+async function pdfSetPermissions(data) {
+  try {
+    const pdfBytes = fs.readFileSync(data.inputPath);
+    const loadOptions = data.currentPassword ? { password: data.currentPassword } : {};
+    const pdf = await PDFDocument.load(pdfBytes, loadOptions);
+
+    const newPdfBytes = await pdf.save({
+      ownerPassword: data.ownerPassword,
+      permissions: {
+        printing: data.permissions.printing ? 'highResolution' : 'lowResolution',
+        modifying: data.permissions.modifying,
+        copying: data.permissions.copying,
+        annotating: data.permissions.annotating,
+        fillingForms: data.permissions.fillingForms,
+        contentAccessibility: data.permissions.contentAccessibility,
+        documentAssembly: data.permissions.documentAssembly
+      }
+    });
+
+    fs.writeFileSync(data.outputPath, newPdfBytes);
+
+    return { success: true, message: 'Successfully updated PDF permissions' };
+  } catch (error) {
+    if (error.message.includes('encrypt') || error.message.includes('permission')) {
+      return {
+        success: false,
+        error: 'PDF permissions require pdf-lib with encryption support. This feature may not be available in the current version.'
+      };
+    }
+    return { success: false, error: error.message };
+  }
+}
+
+function executeOperation(operation, data) {
+  switch (operation) {
+    case 'merge': return pdfMerge(data);
+    case 'split': return pdfSplit(data);
+    case 'compress': return pdfCompress(data);
+    case 'rotate': return pdfRotate(data);
+    case 'delete': return pdfDeletePages(data);
+    case 'reorder': return pdfReorder(data);
+    case 'watermark': return pdfWatermark(data);
+    case 'encrypt': return pdfEncrypt(data);
+    case 'decrypt': return pdfDecrypt(data);
+    case 'permissions': return pdfSetPermissions(data);
+    default: return Promise.resolve({ success: false, error: `Unknown operation: ${operation}` });
+  }
+}
+
+async function getPageCount(filePath) {
+  const pdfBytes = fs.readFileSync(filePath);
+  const pdf = await PDFDocument.load(pdfBytes);
+  return pdf.getPageCount();
+}
+
+module.exports = {
+  parsePageRanges,
+  hexToRgb,
+  pdfMerge,
+  pdfSplit,
+  pdfCompress,
+  pdfRotate,
+  pdfDeletePages,
+  pdfReorder,
+  pdfWatermark,
+  pdfEncrypt,
+  pdfDecrypt,
+  pdfSetPermissions,
+  executeOperation,
+  getPageCount
+};

src/plugins/built-in/_sample/index.js

@@ -0,0 +1,12 @@
+const { PluginAPI } = require('../../plugin-api');
+
+class SamplePlugin extends PluginAPI {
+  init(context) {
+    this.context = context;
+    context.commands.register('hello', 'Sample: Hello World', () => {
+      console.log('[SamplePlugin] Hello from the plugin system!');
+    });
+  }
+}
+
+module.exports = { Plugin: SamplePlugin };

src/plugins/built-in/_sample/manifest.json

@@ -0,0 +1,13 @@
+{
+  "id": "_sample",
+  "name": "Sample Plugin",
+  "version": "1.0.0",
+  "description": "Demonstrates the plugin system. Safe to delete.",
+  "icon": "puzzle",
+  "extensionPoints": {
+    "commands": [
+      { "id": "hello", "label": "Sample: Hello World", "shortcut": "" }
+    ]
+  },
+  "settings": []
+}

src/plugins/built-in/writing-studio/goal-tracker.js

@@ -0,0 +1,87 @@
+const HISTORY_KEY = 'plugins.writing-studio.history';
+
+class GoalTracker {
+  /**
+   * @param {object} store - { get(key), set(key, value) } settings backend
+   */
+  constructor(store) {
+    this.store = store;
+  }
+
+  _getHistory() {
+    const raw = this.store.get(HISTORY_KEY);
+    return raw ? JSON.parse(raw) : {};
+  }
+
+  _setHistory(history) {
+    this.store.set(HISTORY_KEY, JSON.stringify(history));
+  }
+
+  _setHistoryDay(dateStr, data) {
+    const history = this._getHistory();
+    history[dateStr] = data;
+    this._setHistory(history);
+  }
+
+  addWords(count) {
+    const today = new Date().toISOString().split('T')[0];
+    const history = this._getHistory();
+    if (!history[today]) {
+      history[today] = { words: 0, sessions: 0 };
+    }
+    history[today].words += count;
+    history[today].sessions += 1;
+    this._setHistory(history);
+  }
+
+  getDailyProgress(goal) {
+    const today = new Date().toISOString().split('T')[0];
+    const history = this._getHistory();
+    const written = history[today]?.words || 0;
+    return { written, goal, pct: goal > 0 ? Math.min(100, Math.round((written / goal) * 100)) : 0 };
+  }
+
+  getStreak(goal) {
+    const history = this._getHistory();
+    let streak = 0;
+    const d = new Date();
+    for (let i = 0; i < 365; i++) {
+      const key = d.toISOString().split('T')[0];
+      const day = history[key];
+      if (day && day.words >= goal) {
+        streak++;
+        d.setDate(d.getDate() - 1);
+      } else {
+        break;
+      }
+    }
+    return streak;
+  }
+
+  getLast30Days() {
+    const history = this._getHistory();
+    const days = [];
+    const d = new Date();
+    for (let i = 0; i < 30; i++) {
+      const key = d.toISOString().split('T')[0];
+      const day = history[key];
+      days.push({ date: key, words: day?.words || 0 });
+      d.setDate(d.getDate() - 1);
+    }
+    return days.reverse();
+  }
+
+  getWeeklyTotal() {
+    const history = this._getHistory();
+    let total = 0;
+    const d = new Date();
+    for (let i = 0; i < 7; i++) {
+      const key = d.toISOString().split('T')[0];
+      if (history[key]) total += history[key].words || 0;
+      d.setDate(d.getDate() - 1);
+    }
+    return total;
+  }
+}
+
+module.exports = { GoalTracker };

src/plugins/built-in/writing-studio/index.js

@@ -0,0 +1,102 @@
+const { PluginAPI } = require('../../../plugins/plugin-api');
+const { SprintEngine } = require('./sprint-engine');
+const { GoalTracker } = require('./goal-tracker');
+const { SnapshotManager } = require('./snapshot-manager');
+const { ProjectManager } = require('./project-manager');
+
+class WritingStudioPlugin extends PluginAPI {
+  init(context) {
+    this.context = context;
+
+    this.sprintEngine = new SprintEngine({
+      onEvent: (name, data) => context.events.emit(name, data)
+    });
+    this.goalTracker = new GoalTracker(context.settings);
+    this.snapshotManager = new SnapshotManager(context.settings);
+    this.projectManager = new ProjectManager({
+      readFile: (p) => context.ipc.invoke('read-file', p),
+      writeFile: (p, c) => context.ipc.invoke('write-file', p, c),
+      fileExists: (p) => context.ipc.invoke('path-exists', p),
+      listDir: (p) => context.ipc.invoke('list-directory', p)
+    });
+
+    this._engines = {
+      sprint: this.sprintEngine,
+      goals: this.goalTracker,
+      snapshots: this.snapshotManager,
+      projects: this.projectManager
+    };
+
+    this._registerCommands(context);
+    this._registerStatusBar(context);
+  }
+
+  _registerCommands(context) {
+    const { sprintEngine, snapshotManager, goalTracker } = this;
+
+    context.commands.register('start-sprint', 'Studio: Start Sprint', () => {
+      const duration = context.settings.get('sprintDuration') || 25;
+      const content = context.editor.getContent() || '';
+      const words = content.split(/\s+/).filter(Boolean).length;
+      sprintEngine.start(duration, words);
+    }, 'Ctrl+Alt+S');
+
+    context.commands.register('stop-sprint', 'Studio: Stop Sprint', () => {
+      if (!sprintEngine.isActive()) return;
+      const content = context.editor.getContent() || '';
+      const words = content.split(/\s+/).filter(Boolean).length;
+      const result = sprintEngine.stop(words);
+      goalTracker.addWords(result.wordDelta);
+      context.events.emit('sprint:stopped', result);
+    }, 'Ctrl+Alt+Shift+S');
+
+    context.commands.register('take-snapshot', 'Studio: Take Snapshot', () => {
+      const content = context.editor.getContent() || '';
+      snapshotManager.create(content, 'manual');
+      context.events.emit('snapshot:created', {});
+    }, 'Ctrl+Alt+N');
+
+    context.commands.register('restore-last-snapshot', 'Studio: Restore Last Snapshot', () => {
+      const snaps = snapshotManager.list();
+      if (snaps.length === 0) return;
+      const content = snapshotManager.restore(snaps[0].id);
+      context.editor.insertAtCursor(content);
+    }, 'Ctrl+Alt+Z');
+
+    context.commands.register('new-project', 'Studio: New Project', () => {
+      context.events.emit('studio:new-project', {});
+    });
+
+    context.commands.register('compile-manuscript', 'Studio: Compile Manuscript', () => {
+      context.events.emit('studio:compile', {});
+    }, 'Ctrl+Alt+E');
+
+    context.commands.register('proofread-document', 'Studio: Proofread Document', () => {
+      if (context.events.hasHandler('ai:analyze')) {
+        const content = context.editor.getContent() || '';
+        context.events.emit('ai:analyze', { text: content, type: 'grammar' });
+      }
+    }, 'Ctrl+Alt+G');
+  }
+
+  _registerStatusBar(context) {
+    context.statusBar.registerIndicator('word-goal', {
+      text: '0/1000',
+      tooltip: 'Daily word goal progress'
+    });
+    context.statusBar.registerIndicator('sprint-timer', {
+      text: '',
+      tooltip: 'Writing sprint timer'
+    });
+  }
+
+  deactivate() {
+    if (this._sprintInterval) clearInterval(this._sprintInterval);
+  }
+
+  getEngines() {
+    return this._engines;
+  }
+}
+
+module.exports = { Plugin: WritingStudioPlugin };

src/plugins/built-in/writing-studio/manifest.json

@@ -0,0 +1,31 @@
+{
+  "id": "writing-studio",
+  "name": "Writing Studio",
+  "version": "1.0.0",
+  "description": "Manuscript management, writing sprints, goal tracking, snapshots, and smart proofreading",
+  "icon": "pen-tool",
+  "extensionPoints": {
+    "sidebar": [
+      { "id": "manuscript", "title": "Manuscript", "order": 30 },
+      { "id": "goals", "title": "Goals", "order": 31 },
+      { "id": "snapshots", "title": "Snapshots", "order": 32 },
+      { "id": "proofread", "title": "Proofread", "order": 33 }
+    ],
+    "commands": [
+      { "id": "start-sprint", "label": "Studio: Start Sprint", "shortcut": "Ctrl+Alt+S" },
+      { "id": "stop-sprint", "label": "Studio: Stop Sprint", "shortcut": "Ctrl+Alt+Shift+S" },
+      { "id": "take-snapshot", "label": "Studio: Take Snapshot", "shortcut": "Ctrl+Alt+N" },
+      { "id": "restore-last-snapshot", "label": "Studio: Restore Last Snapshot", "shortcut": "Ctrl+Alt+Z" },
+      { "id": "new-project", "label": "Studio: New Project", "shortcut": "" },
+      { "id": "compile-manuscript", "label": "Studio: Compile Manuscript", "shortcut": "Ctrl+Alt+E" },
+      { "id": "proofread-document", "label": "Studio: Proofread Document", "shortcut": "Ctrl+Alt+G" }
+    ],
+    "statusBar": { "indicators": ["sprint-timer", "word-goal"] }
+  },
+  "settings": [
+    { "key": "dailyGoal", "type": "number", "default": 1000, "label": "Daily word goal" },
+    { "key": "sprintDuration", "type": "number", "default": 25, "label": "Sprint duration (min)" },
+    { "key": "autoSnapshotInterval", "type": "number", "default": 0, "label": "Auto-snapshot interval (min, 0=off)" },
+    { "key": "maxSnapshots", "type": "number", "default": 50, "label": "Max snapshots to keep" }
+  ]
+}

src/plugins/built-in/writing-studio/panels/goals-panel.js

@@ -0,0 +1,99 @@
+function renderGoalsPanel(container, { engines, settings }) {
+  const dailyGoal = settings.get('dailyGoal') || 1000;
+  const progress = engines.goals.getDailyProgress(dailyGoal);
+  const streak = engines.goals.getStreak(dailyGoal);
+  const weekly = engines.goals.getWeeklyTotal();
+  const last30 = engines.goals.getLast30Days();
+
+  container.replaceChildren();
+
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  // Daily progress section
+  const section1 = document.createElement('div');
+  section1.className = 'ws-section';
+  const heading1 = document.createElement('h3');
+  heading1.className = 'ws-heading';
+  heading1.textContent = 'Daily Progress';
+  section1.appendChild(heading1);
+
+  const bar = document.createElement('div');
+  bar.className = 'ws-progress-bar';
+  const fill = document.createElement('div');
+  fill.className = 'ws-progress-fill';
+  fill.style.width = progress.pct + '%';
+  bar.appendChild(fill);
+  section1.appendChild(bar);
+
+  const row = document.createElement('div');
+  row.className = 'ws-stat-row';
+  const label = document.createElement('span');
+  label.textContent = progress.written.toLocaleString() + ' / ' + dailyGoal.toLocaleString() + ' words';
+  const pct = document.createElement('span');
+  pct.className = 'ws-pct';
+  pct.textContent = progress.pct + '%';
+  row.appendChild(label);
+  row.appendChild(pct);
+  section1.appendChild(row);
+  panel.appendChild(section1);
+
+  // Stats cards
+  const section2 = document.createElement('div');
+  section2.className = 'ws-section';
+  const grid = document.createElement('div');
+  grid.className = 'ws-stat-grid';
+
+  const streakCard = document.createElement('div');
+  streakCard.className = 'ws-stat-card';
+  const streakVal = document.createElement('span');
+  streakVal.className = 'ws-stat-value';
+  streakVal.textContent = String(streak);
+  const streakLbl = document.createElement('span');
+  streakLbl.className = 'ws-stat-label';
+  streakLbl.textContent = 'Day Streak';
+  streakCard.appendChild(streakVal);
+  streakCard.appendChild(streakLbl);
+
+  const weekCard = document.createElement('div');
+  weekCard.className = 'ws-stat-card';
+  const weekVal = document.createElement('span');
+  weekVal.className = 'ws-stat-value';
+  weekVal.textContent = weekly.toLocaleString();
+  const weekLbl = document.createElement('span');
+  weekLbl.className = 'ws-stat-label';
+  weekLbl.textContent = 'This Week';
+  weekCard.appendChild(weekVal);
+  weekCard.appendChild(weekLbl);
+
+  grid.appendChild(streakCard);
+  grid.appendChild(weekCard);
+  section2.appendChild(grid);
+  panel.appendChild(section2);
+
+  // 30-day chart
+  const section3 = document.createElement('div');
+  section3.className = 'ws-section';
+  const heading3 = document.createElement('h3');
+  heading3.className = 'ws-heading';
+  heading3.textContent = 'Last 30 Days';
+  section3.appendChild(heading3);
+
+  const chart = document.createElement('div');
+  chart.className = 'ws-chart';
+  const maxWords = Math.max(...last30.map(d => d.words), 1);
+  for (const day of last30) {
+    const barEl = document.createElement('div');
+    const height = Math.max(2, (day.words / maxWords) * 60);
+    barEl.className = 'ws-bar' + (day.words >= dailyGoal ? ' ws-bar-met' : '');
+    barEl.style.height = height + 'px';
+    barEl.title = day.date + ': ' + day.words + ' words';
+    chart.appendChild(barEl);
+  }
+  section3.appendChild(chart);
+  panel.appendChild(section3);
+
+  container.appendChild(panel);
+}
+
+module.exports = { renderGoalsPanel };

src/plugins/built-in/writing-studio/panels/manuscript-panel.js

@@ -0,0 +1,124 @@
+function renderManuscriptPanel(container, { engines, editor, settings }) {
+  const projectDir = settings.get('projectDir');
+
+  container.replaceChildren();
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  if (!projectDir) {
+    const empty = document.createElement('div');
+    empty.className = 'ws-empty';
+    const p = document.createElement('p');
+    p.textContent = 'No manuscript project open';
+    empty.appendChild(p);
+    const btn = document.createElement('button');
+    btn.className = 'ws-btn ws-btn-primary';
+    btn.id = 'ws-new-project';
+    btn.textContent = 'New Project';
+    btn.addEventListener('click', () => {
+      const name = prompt('Project name:');
+      if (!name) return;
+      settings.set('projectDir', name);
+      renderManuscriptPanel(container, { engines, editor, settings });
+    });
+    empty.appendChild(btn);
+    panel.appendChild(empty);
+    container.appendChild(panel);
+    return;
+  }
+
+  const project = engines.projects.loadProject(projectDir);
+  if (!project) {
+    const empty = document.createElement('div');
+    empty.className = 'ws-empty';
+    const p = document.createElement('p');
+    p.textContent = 'Project not found at ' + projectDir;
+    empty.appendChild(p);
+    const btn = document.createElement('button');
+    btn.className = 'ws-btn';
+    btn.id = 'ws-clear-project';
+    btn.textContent = 'Clear Project';
+    btn.addEventListener('click', () => {
+      settings.set('projectDir', null);
+      renderManuscriptPanel(container, { engines, editor, settings });
+    });
+    empty.appendChild(btn);
+    panel.appendChild(empty);
+    container.appendChild(panel);
+    return;
+  }
+
+  const stats = engines.projects.getStats(projectDir);
+
+  // Project title + progress
+  const section1 = document.createElement('div');
+  section1.className = 'ws-section';
+  const heading = document.createElement('h3');
+  heading.className = 'ws-heading';
+  heading.textContent = project.title;
+  section1.appendChild(heading);
+
+  const bar = document.createElement('div');
+  bar.className = 'ws-progress-bar';
+  const fill = document.createElement('div');
+  fill.className = 'ws-progress-fill';
+  fill.style.width = stats.pctComplete + '%';
+  bar.appendChild(fill);
+  section1.appendChild(bar);
+
+  const row = document.createElement('div');
+  row.className = 'ws-stat-row';
+  const label = document.createElement('span');
+  label.textContent = stats.totalWords.toLocaleString() + ' / ' + stats.targetWords.toLocaleString() + ' words';
+  const pct = document.createElement('span');
+  pct.className = 'ws-pct';
+  pct.textContent = stats.pctComplete + '%';
+  row.appendChild(label);
+  row.appendChild(pct);
+  section1.appendChild(row);
+  panel.appendChild(section1);
+
+  // Chapters list
+  const section2 = document.createElement('div');
+  section2.className = 'ws-section';
+  const heading2 = document.createElement('h3');
+  heading2.className = 'ws-heading';
+  heading2.textContent = 'Chapters (' + project.chapters.length + ')';
+  section2.appendChild(heading2);
+
+  const chList = document.createElement('div');
+  chList.className = 'ws-chapter-list';
+  for (const ch of project.chapters) {
+    const item = document.createElement('div');
+    item.className = 'ws-chapter-item';
+    const title = document.createElement('span');
+    title.className = 'ws-chapter-title';
+    title.textContent = ch.title || ch.file;
+    const status = document.createElement('span');
+    status.className = 'ws-chapter-status ws-status-' + (ch.status || 'draft');
+    status.textContent = ch.status || 'draft';
+    item.appendChild(title);
+    item.appendChild(status);
+    chList.appendChild(item);
+  }
+  section2.appendChild(chList);
+  panel.appendChild(section2);
+
+  // Compile button
+  const section3 = document.createElement('div');
+  section3.className = 'ws-section';
+  const compileBtn = document.createElement('button');
+  compileBtn.className = 'ws-btn ws-btn-primary';
+  compileBtn.id = 'ws-compile';
+  compileBtn.textContent = 'Compile Manuscript';
+  compileBtn.addEventListener('click', () => {
+    const compiled = engines.projects.compileManuscript(projectDir);
+    editor.insertAtCursor(compiled);
+  });
+  section3.appendChild(compileBtn);
+  panel.appendChild(section3);
+
+  container.appendChild(panel);
+}
+
+module.exports = { renderManuscriptPanel };

src/plugins/built-in/writing-studio/panels/proofread-panel.js

@@ -0,0 +1,97 @@
+function renderProofreadPanel(container, { events, editor }) {
+  const hasAI = events.hasHandler('ai:analyze');
+
+  container.replaceChildren();
+
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  const section = document.createElement('div');
+  section.className = 'ws-section';
+
+  const btn = document.createElement('button');
+  btn.className = 'ws-btn ws-btn-primary';
+  btn.id = 'ws-proofread';
+  btn.textContent = hasAI ? 'Check Document' : 'AI Plugin Required';
+  btn.disabled = !hasAI;
+  section.appendChild(btn);
+
+  if (!hasAI) {
+    const note = document.createElement('p');
+    note.className = 'ws-muted';
+    note.textContent = 'Install the AI Assistant plugin to enable proofreading.';
+    section.appendChild(note);
+  }
+  panel.appendChild(section);
+
+  const issuesList = document.createElement('div');
+  issuesList.className = 'ws-issues-list';
+  issuesList.id = 'ws-issues';
+  panel.appendChild(issuesList);
+
+  container.appendChild(panel);
+
+  if (!hasAI) return;
+
+  container.querySelector('#ws-proofread').addEventListener('click', () => {
+    const content = editor.getContent() || '';
+    events.emit('ai:analyze', {
+      text: content,
+      type: 'grammar',
+      callback: (result) => {
+        if (result && result.issues) {
+          renderIssues(issuesList, result.issues);
+        }
+      }
+    });
+  });
+}
+
+function renderIssues(container, issues) {
+  container.replaceChildren();
+  if (!issues || issues.length === 0) {
+    const p = document.createElement('p');
+    p.className = 'ws-muted';
+    p.textContent = 'No issues found.';
+    container.appendChild(p);
+    return;
+  }
+  for (let i = 0; i < issues.length; i++) {
+    const issue = issues[i];
+    const item = document.createElement('div');
+    item.className = 'ws-issue-item';
+
+    const type = document.createElement('div');
+    type.className = 'ws-issue-type';
+    type.textContent = (issue.type || 'grammar').toUpperCase();
+    item.appendChild(type);
+
+    const text = document.createElement('div');
+    text.className = 'ws-issue-text';
+    text.textContent = issue.message || issue.text || '';
+    item.appendChild(text);
+
+    if (issue.suggestion) {
+      const sug = document.createElement('div');
+      sug.className = 'ws-issue-suggestion';
+      sug.textContent = 'Suggestion: ' + issue.suggestion;
+      item.appendChild(sug);
+    }
+
+    const actions = document.createElement('div');
+    actions.className = 'ws-issue-actions';
+    for (const [action, label] of [['accept', 'Accept'], ['dismiss', 'Dismiss']]) {
+      const actionBtn = document.createElement('button');
+      actionBtn.className = 'ws-btn ws-btn-sm';
+      actionBtn.textContent = label;
+      actionBtn.addEventListener('click', () => {
+        item.remove();
+      });
+      actions.appendChild(actionBtn);
+    }
+    item.appendChild(actions);
+    container.appendChild(item);
+  }
+}
+
+module.exports = { renderProofreadPanel };

src/plugins/built-in/writing-studio/panels/snapshots-panel.js

@@ -0,0 +1,81 @@
+function renderSnapshotsPanel(container, { engines, editor }) {
+  const snapshots = engines.snapshots.list();
+
+  container.replaceChildren();
+
+  const panel = document.createElement('div');
+  panel.className = 'ws-panel';
+
+  // Header with take snapshot button
+  const section = document.createElement('div');
+  section.className = 'ws-section';
+  const btn = document.createElement('button');
+  btn.className = 'ws-btn ws-btn-primary';
+  btn.id = 'ws-take-snapshot';
+  btn.textContent = 'Take Snapshot';
+  section.appendChild(btn);
+  const count = document.createElement('span');
+  count.className = 'ws-muted';
+  count.textContent = snapshots.length + ' snapshots';
+  section.appendChild(count);
+  panel.appendChild(section);
+
+  // Snapshot list
+  const list = document.createElement('div');
+  list.className = 'ws-snapshot-list';
+  for (const s of snapshots) {
+    const item = document.createElement('div');
+    item.className = 'ws-snapshot-item';
+
+    const header = document.createElement('div');
+    header.className = 'ws-snapshot-header';
+    const sLabel = document.createElement('span');
+    sLabel.className = 'ws-snapshot-label';
+    sLabel.textContent = s.label;
+    const sWords = document.createElement('span');
+    sWords.textContent = s.wordCount + ' words';
+    header.appendChild(sLabel);
+    header.appendChild(sWords);
+    item.appendChild(header);
+
+    const time = document.createElement('div');
+    time.className = 'ws-snapshot-time';
+    time.textContent = new Date(s.timestamp).toLocaleString();
+    item.appendChild(time);
+
+    const actions = document.createElement('div');
+    actions.className = 'ws-snapshot-actions';
+    for (const [action, text, cls] of [['restore', 'Restore', ''], ['diff', 'Diff', ''], ['delete', 'Delete', 'ws-btn-danger']]) {
+      const actionBtn = document.createElement('button');
+      actionBtn.className = 'ws-btn ws-btn-sm' + (cls ? ' ' + cls : '');
+      actionBtn.textContent = text;
+      actionBtn.addEventListener('click', () => {
+        if (action === 'restore') {
+          const content = engines.snapshots.restore(s.id);
+          editor.insertAtCursor(content);
+        } else if (action === 'delete') {
+          engines.snapshots.delete(s.id);
+          renderSnapshotsPanel(container, { engines, editor });
+        } else if (action === 'diff') {
+          const current = editor.getContent() || '';
+          const result = engines.snapshots.diff(s.id, current);
+          alert('+' + result.added + ' lines added, -' + result.removed + ' lines removed');
+        }
+      });
+      actions.appendChild(actionBtn);
+    }
+    item.appendChild(actions);
+    list.appendChild(item);
+  }
+  panel.appendChild(list);
+  container.appendChild(panel);
+
+  // Take snapshot button handler
+  container.querySelector('#ws-take-snapshot').addEventListener('click', () => {
+    const content = editor.getContent() || '';
+    engines.snapshots.create(content, 'manual');
+    renderSnapshotsPanel(container, { engines, editor });
+  });
+}
+
+module.exports = { renderSnapshotsPanel };

src/plugins/built-in/writing-studio/project-manager.js

@@ -0,0 +1,74 @@
+class ProjectManager {
+  /**
+   * @param {object} fs - { readFile(path), writeFile(path, content), fileExists(path), listDir(path) }
+   */
+  constructor(fs) {
+    this.fs = fs;
+  }
+
+  createProject(dir, opts) {
+    const project = {
+      title: opts.title,
+      type: opts.type || 'manuscript',
+      target: { words: opts.targetWords || 0, deadline: opts.deadline || null },
+      chapters: [],
+      metadata: opts.metadata || {}
+    };
+    this.fs.writeFile(dir + '/.project.json', JSON.stringify(project, null, 2));
+    return project;
+  }
+
+  loadProject(dir) {
+    const raw = this.fs.readFile(dir + '/.project.json');
+    if (!raw) return null;
+    return JSON.parse(raw);
+  }
+
+  _saveProject(dir, project) {
+    this.fs.writeFile(dir + '/.project.json', JSON.stringify(project, null, 2));
+  }
+
+  addChapter(dir, chapter) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    project.chapters.push(chapter);
+    this._saveProject(dir, project);
+  }
+
+  updateChapter(dir, index, updates) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    Object.assign(project.chapters[index], updates);
+    this._saveProject(dir, project);
+  }
+
+  compileManuscript(dir) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    const parts = [];
+    for (const ch of project.chapters) {
+      const content = this.fs.readFile(dir + '/' + ch.file);
+      if (content) parts.push(content);
+    }
+    return parts.join('\n\n---\n\n');
+  }
+
+  getStats(dir) {
+    const project = this.loadProject(dir);
+    if (!project) throw new Error('Project not found');
+    let totalWords = 0;
+    for (const ch of project.chapters) {
+      const content = this.fs.readFile(dir + '/' + ch.file);
+      if (content) totalWords += content.split(/\s+/).filter(Boolean).length;
+    }
+    const target = project.target.words || 0;
+    return {
+      totalWords,
+      chapterCount: project.chapters.length,
+      targetWords: target,
+      pctComplete: target > 0 ? Math.min(100, Math.round((totalWords / target) * 100)) : 0
+    };
+  }
+}
+
+module.exports = { ProjectManager };

src/plugins/built-in/writing-studio/snapshot-manager.js

@@ -0,0 +1,73 @@
+class SnapshotManager {
+  /**
+   * @param {object} store - { get(key), set(key, value) }
+   * @param {string} storeKey - settings key for snapshots
+   */
+  constructor(store, storeKey = 'plugins.writing-studio.snapshots') {
+    this.store = store;
+    this.storeKey = storeKey;
+  }
+
+  _getAll() {
+    const raw = this.store.get(this.storeKey);
+    return raw ? JSON.parse(raw) : [];
+  }
+
+  _saveAll(snaps) {
+    this.store.set(this.storeKey, JSON.stringify(snaps));
+  }
+
+  create(content, label = 'manual') {
+    const snaps = this._getAll();
+    const snap = {
+      id: 'snap-' + Date.now() + '-' + Math.random().toString(36).slice(2, 8),
+      timestamp: new Date().toISOString(),
+      content,
+      wordCount: content.split(/\s+/).filter(Boolean).length,
+      label
+    };
+    snaps.unshift(snap);
+    this._saveAll(snaps);
+    return snap;
+  }
+
+  list() {
+    return this._getAll();
+  }
+
+  getById(id) {
+    return this._getAll().find(s => s.id === id) || null;
+  }
+
+  restore(id) {
+    const snap = this.getById(id);
+    if (!snap) throw new Error('Snapshot not found');
+    return snap.content;
+  }
+
+  delete(id) {
+    const snaps = this._getAll().filter(s => s.id !== id);
+    this._saveAll(snaps);
+  }
+
+  diff(id, currentContent) {
+    const snap = this.getById(id);
+    if (!snap) throw new Error('Snapshot not found');
+    const oldLines = snap.content.split('\n');
+    const newLines = currentContent.split('\n');
+    const oldSet = new Set(oldLines);
+    const newSet = new Set(newLines);
+    let added = 0;
+    let removed = 0;
+    for (const line of newLines) { if (!oldSet.has(line)) added++; }
+    for (const line of oldLines) { if (!newSet.has(line)) removed++; }
+    return { added, removed };
+  }
+
+  prune(keepCount) {
+    const snaps = this._getAll();
+    this._saveAll(snaps.slice(0, keepCount));
+  }
+}
+
+module.exports = { SnapshotManager };

src/plugins/built-in/writing-studio/sprint-engine.js

@@ -0,0 +1,51 @@
+class SprintEngine {
+  /**
+   * @param {object} opts
+   * @param {function} opts.onEvent - callback(event_name, data)
+   */
+  constructor(opts = {}) {
+    this.onEvent = opts.onEvent || (() => {});
+    this._active = false;
+    this._startTime = null;
+    this._duration = 0;
+    this._initialWords = 0;
+  }
+
+  start(durationMinutes, currentWordCount) {
+    if (this._active) throw new Error('Sprint already active');
+    this._active = true;
+    this._startTime = Date.now();
+    this._duration = durationMinutes * 60 * 1000;
+    this._initialWords = currentWordCount;
+  }
+
+  stop(currentWordCount) {
+    if (!this._active) throw new Error('No active sprint');
+    const elapsed = Date.now() - this._startTime;
+    const wordDelta = Math.max(0, currentWordCount - this._initialWords);
+    const elapsedMinutes = elapsed / 60000;
+    const wpm = elapsedMinutes > 0 ? Math.round(wordDelta / elapsedMinutes) : 0;
+    this._active = false;
+    this._startTime = null;
+    return { wordDelta, elapsed, wpm };
+  }
+
+  tick(elapsedMs) {
+    if (!this._active) return;
+    const remaining = Math.max(0, this._duration - elapsedMs);
+    this.onEvent('sprint:tick', { remaining, elapsed: elapsedMs });
+    if (remaining <= 0) {
+      this._active = false;
+      this.onEvent('sprint:complete', { expired: true });
+    }
+  }
+
+  isActive() { return this._active; }
+
+  getRemaining() {
+    if (!this._active) return 0;
+    return Math.max(0, this._duration - (Date.now() - this._startTime));
+  }
+}
+
+module.exports = { SprintEngine };

src/plugins/event-bus.js

@@ -0,0 +1,43 @@
+class EventBus {
+  constructor() {
+    this.listeners = new Map();
+  }
+
+  on(event, handler) {
+    if (!this.listeners.has(event)) {
+      this.listeners.set(event, []);
+    }
+    this.listeners.get(event).push(handler);
+  }
+
+  off(event, handler) {
+    if (!handler) {
+      this.listeners.delete(event);
+      return;
+    }
+    const handlers = this.listeners.get(event);
+    if (handlers) {
+      const idx = handlers.indexOf(handler);
+      if (idx !== -1) handlers.splice(idx, 1);
+    }
+  }
+
+  emit(event, payload) {
+    const handlers = this.listeners.get(event);
+    if (!handlers) return;
+    for (const handler of handlers) {
+      try {
+        handler(payload);
+      } catch (err) {
+        console.error(`[EventBus] Error in handler for "${event}":`, err);
+      }
+    }
+  }
+
+  hasHandler(event) {
+    const handlers = this.listeners.get(event);
+    return handlers !== undefined && handlers !== null && handlers.length > 0;
+  }
+}
+
+module.exports = { EventBus };

src/plugins/plugin-api.js

@@ -0,0 +1,23 @@
+class PluginAPI {
+  /**
+   * Called when the plugin is discovered and loaded.
+   * Receives a scoped context object with APIs.
+   * @param {object} context - Plugin context (sidebar, commands, settings, etc.)
+   */
+  init(context) {
+    this.context = context;
+  }
+
+  /** Called when the plugin is activated (e.g., sidebar panel clicked). */
+  activate() {}
+
+  /** Called when the plugin is deactivated. */
+  deactivate() {}
+
+  /** Returns the parsed manifest.json for this plugin. */
+  getManifest() {
+    return this._manifest || null;
+  }
+}
+
+module.exports = { PluginAPI };

src/plugins/plugin-context.js

@@ -0,0 +1,70 @@
+class PluginContext {
+  /**
+   * @param {object} deps - Injected dependencies
+   * @param {string} deps.pluginId - Plugin unique ID (for namespacing)
+   * @param {object} deps.sidebar - SidebarManager.registerPanel
+   * @param {object} deps.commands - CommandPalette.register
+   * @param {object} deps.statusBar - StatusBar.registerIndicator
+   * @param {object} deps.eventBus - EventBus instance
+   * @param {object} deps.settings - { get, set, onChanged }
+   * @param {object} deps.editor - { getContent, getSelection, insertAtCursor, onContentChanged }
+   * @param {object} deps.ipc - { invoke, on }
+   * @param {object} deps.exportHooks - { preHooks: [], postHooks: [] }
+   */
+  constructor(deps) {
+    const { pluginId, sidebar, commands, statusBar, eventBus, settings, editor, ipc, exportHooks } = deps;
+
+    this.sidebar = {
+      registerPanel: (id, opts) => sidebar.registerPanel(`${pluginId}:${id}`, opts)
+    };
+
+    this.commands = {
+      register: (id, label, handler, shortcut) => {
+        const safeHandler = (...args) => {
+          try {
+            handler(...args);
+          } catch (err) {
+            console.error(`[Plugin:${pluginId}] Command "${id}" error:`, err);
+          }
+        };
+        commands.register(`${pluginId}:${id}`, label, safeHandler, shortcut);
+      }
+    };
+
+    this.statusBar = {
+      registerIndicator: (id, opts) => statusBar.registerIndicator(`${pluginId}:${id}`, opts)
+    };
+
+    this.settings = {
+      get: (key) => settings.get(`plugins.${pluginId}.${key}`),
+      set: (key, value) => settings.set(`plugins.${pluginId}.${key}`, value),
+      onChanged: (key, cb) => settings.onChanged(`plugins.${pluginId}.${key}`, cb)
+    };
+
+    this.editor = {
+      getContent: () => editor.getContent(),
+      getSelection: () => editor.getSelection(),
+      insertAtCursor: (text) => editor.insertAtCursor(text),
+      onContentChanged: (cb) => editor.onContentChanged(cb)
+    };
+
+    this.events = {
+      on: (event, handler) => eventBus.on(event, handler),
+      off: (event, handler) => eventBus.off(event, handler),
+      emit: (event, payload) => eventBus.emit(event, payload),
+      hasHandler: (event) => eventBus.hasHandler(event)
+    };
+
+    this.ipc = {
+      invoke: (channel, ...args) => ipc.invoke(channel, ...args),
+      on: (channel, handler) => ipc.on(channel, handler)
+    };
+
+    this.exports = {
+      registerPreHook: (handler) => { if (exportHooks) exportHooks.preHooks.push(handler); },
+      registerPostHook: (handler) => { if (exportHooks) exportHooks.postHooks.push(handler); }
+    };
+  }
+}
+
+module.exports = { PluginContext };

src/plugins/plugin-loader.js

@@ -0,0 +1,75 @@
+const fs = require('fs');
+const path = require('path');
+
+class PluginLoader {
+  /**
+   * @param {string[]} searchDirs - Directories to scan for plugin folders
+   */
+  constructor(searchDirs = []) {
+    this.searchDirs = searchDirs;
+    this.loadedIds = new Set();
+  }
+
+  /**
+   * Discover plugins by scanning searchDirs for manifest.json files.
+   * Returns array of { id, name, version, description, manifest, PluginClass, dir }
+   */
+  discoverPlugins() {
+    const plugins = [];
+    for (const dir of this.searchDirs) {
+      if (!fs.existsSync(dir)) continue;
+      const entries = fs.readdirSync(dir, { withFileTypes: true });
+      for (const entry of entries) {
+        if (!entry.isDirectory()) continue;
+        const pluginDir = path.join(dir, entry.name);
+        const manifestPath = path.join(pluginDir, 'manifest.json');
+        if (!fs.existsSync(manifestPath)) continue;
+        try {
+          const raw = fs.readFileSync(manifestPath, 'utf-8');
+          const manifest = JSON.parse(raw);
+          this.validateManifest(manifest);
+          let PluginClass = null;
+          const indexPath = path.join(pluginDir, 'index.js');
+          if (fs.existsSync(indexPath)) {
+            try {
+              const loaded = require(indexPath);
+              PluginClass = loaded.Plugin || loaded.default || null;
+            } catch (err) {
+              console.error(`[PluginLoader] Failed to load index.js for "${manifest.id}":`, err.message);
+              continue;
+            }
+          }
+          plugins.push({
+            id: manifest.id,
+            name: manifest.name,
+            version: manifest.version,
+            description: manifest.description,
+            manifest,
+            PluginClass,
+            dir: pluginDir
+          });
+          this.loadedIds.add(manifest.id);
+        } catch (err) {
+          console.error(`[PluginLoader] Skipping plugin in ${pluginDir}:`, err.message);
+        }
+      }
+    }
+    return plugins;
+  }
+
+  /**
+   * Validate a manifest object. Throws on invalid.
+   */
+  validateManifest(manifest) {
+    if (!manifest.id) throw new Error('Manifest missing required field: id');
+    if (!manifest.name) throw new Error('Manifest missing required field: name');
+    if (!manifest.version) throw new Error('Manifest missing required field: version');
+    if (!manifest.description) throw new Error('Manifest missing required field: description');
+    if (this.loadedIds.has(manifest.id)) {
+      throw new Error(`Duplicate plugin id: "${manifest.id}"`);
+    }
+    return true;
+  }
+}
+
+module.exports = { PluginLoader };

src/plugins/plugin-registry.js

@@ -0,0 +1,80 @@
+const { PluginContext } = require('./plugin-context');
+const { PluginAPI } = require('./plugin-api');
+
+class PluginRegistry {
+  constructor(deps) {
+    this.deps = deps;
+    this.plugins = new Map();
+    this.exportHooks = { preHooks: [], postHooks: [] };
+  }
+
+  /**
+   * Register a discovered plugin. Creates instance, builds context, calls init.
+   * If init throws, plugin is NOT registered.
+   */
+  register(pluginInfo) {
+    const { id, name, version, description, manifest, PluginClass, dir } = pluginInfo;
+
+    let instance;
+    if (PluginClass) {
+      instance = new PluginClass();
+    } else {
+      instance = new PluginAPI();
+    }
+    instance._manifest = manifest;
+
+    const context = new PluginContext({
+      pluginId: id,
+      sidebar: this.deps.sidebar,
+      commands: this.deps.commands,
+      statusBar: this.deps.statusBar,
+      eventBus: this.deps.eventBus,
+      settings: this.deps.settings,
+      editor: this.deps.editor,
+      ipc: this.deps.ipc,
+      exportHooks: this.exportHooks
+    });
+
+    try {
+      instance.init(context);
+    } catch (err) {
+      console.error(`[PluginRegistry] Plugin "${id}" init failed:`, err.message);
+      return;
+    }
+
+    this.plugins.set(id, { id, name, version, description, manifest, instance, dir, context });
+    console.log(`[PluginRegistry] Registered plugin: ${name} v${version}`);
+  }
+
+  getPlugin(id) {
+    return this.plugins.get(id);
+  }
+
+  getAll() {
+    return Array.from(this.plugins.values());
+  }
+
+  activate(id) {
+    const plugin = this.plugins.get(id);
+    if (plugin?.instance) {
+      try {
+        plugin.instance.activate();
+      } catch (err) {
+        console.error(`[PluginRegistry] Plugin "${id}" activate error:`, err.message);
+      }
+    }
+  }
+
+  deactivate(id) {
+    const plugin = this.plugins.get(id);
+    if (plugin?.instance) {
+      try {
+        plugin.instance.deactivate();
+      } catch (err) {
+        console.error(`[PluginRegistry] Plugin "${id}" deactivate error:`, err.message);
+      }
+    }
+  }
+}
+
+module.exports = { PluginRegistry };

src/plugins/settings-store.js

@@ -0,0 +1,23 @@
+class SettingsStore {
+  /**
+   * @param {object} backend - { get(key), set(key, value) } backed by main process store
+   */
+  constructor(backend) {
+    this.backend = backend;
+  }
+
+  get(key) {
+    return this.backend.get(key);
+  }
+
+  set(key, value) {
+    this.backend.set(key, value);
+  }
+
+  onChanged(key, callback) {
+    // Deferred: plugins read settings on init/activate for MVP.
+    // Full change notification requires IPC watcher in main process.
+  }
+}
+
+module.exports = { SettingsStore };

src/preload.js

@@ -9,7 +9,7 @@
  * - All IPC channels are explicitly whitelisted
  * - Prevents XSS from escalating to full system access
  *
- * @version 4.0.0
+ * @version 4.4.1
  */
 
 const { contextBridge, ipcRenderer } = require('electron');
@@ -101,6 +101,14 @@ const ALLOWED_SEND_CHANNELS = [
 
   // File Explorer
   'list-directory',
+  'read-file',
+  'write-file',
+  'delete-file',
+  'ensure-directory',
+  'path-exists',
+  'is-directory',
+  'copy-path',
+  'move-path',
 
   // Git
   'git-status',
@@ -127,7 +135,11 @@ const ALLOWED_SEND_CHANNELS = [
   'export',
 
   // Git diff
-  'git-diff'
+  'git-diff',
+
+  // Plugin settings
+  'plugin-settings:get',
+  'plugin-settings:set'
 ];
 
 const ALLOWED_RECEIVE_CHANNELS = [
@@ -321,7 +333,15 @@ contextBridge.exposeInMainWorld('electronAPI', {
     setCurrent: (filePath) => ipcRenderer.send('set-current-file', filePath),
     saveRecent: (recentFiles) => ipcRenderer.send('save-recent-files', recentFiles),
     clearRecent: () => ipcRenderer.send('clear-recent-files'),
-    rendererReady: () => ipcRenderer.send('renderer-ready')
+    rendererReady: () => ipcRenderer.send('renderer-ready'),
+    read: (filePath) => ipcRenderer.invoke('read-file', filePath),
+    write: (filePath, content) => ipcRenderer.invoke('write-file', { path: filePath, content }),
+    delete: (filePath) => ipcRenderer.invoke('delete-file', filePath),
+    ensureDir: (dirPath) => ipcRenderer.invoke('ensure-directory', dirPath),
+    exists: (filePath) => ipcRenderer.invoke('path-exists', filePath),
+    isDirectory: (filePath) => ipcRenderer.invoke('is-directory', filePath),
+    copy: (source, destination) => ipcRenderer.invoke('copy-path', { source, destination }),
+    move: (source, destination) => ipcRenderer.invoke('move-path', { source, destination })
   },
 
   // Theme Operations
@@ -413,7 +433,9 @@ contextBridge.exposeInMainWorld('electronAPI', {
   generators: {
     openAscii: () => ipcRenderer.send('open-ascii-generator'),
     openTable: () => ipcRenderer.send('open-table-generator')
-  }
+  },
+
+  getAppVersion: () => ipcRenderer.invoke('get-app-version')
 });
 
 // Log successful preload initialization

src/print-preview.js

@@ -1,19 +1,28 @@
 class PrintPreview {
     constructor() {
         this.overlay = document.getElementById('print-preview-overlay');
+        this.modal = window.modals?.printPreviewModal;
         this._lastContent = '';
         this.setupEventListeners();
     }
 
     open(htmlContent) {
         this._lastContent = htmlContent;
-        this.overlay.classList.remove('hidden');
+        if (this.modal) {
+            this.modal.open();
+        } else {
+            this.overlay.classList.remove('hidden');
+        }
         this.updatePreview(htmlContent);
         this.updateScaleLabel();
     }
 
     close() {
-        this.overlay.classList.add('hidden');
+        if (this.modal) {
+            this.modal.close();
+        } else {
+            this.overlay.classList.add('hidden');
+        }
     }
 
     setupEventListeners() {
@@ -38,17 +47,7 @@ class PrintPreview {
             }
         });
 
-        // Close on overlay click
-        this.overlay?.addEventListener('click', (e) => {
-            if (e.target === this.overlay) this.close();
-        });
-
-        // Close on Escape
-        document.addEventListener('keydown', (e) => {
-            if (e.key === 'Escape' && !this.overlay.classList.contains('hidden')) {
-                this.close();
-            }
-        });
+        // Note: Backdrop click and Escape key are now handled by ModalManager
     }
 
     updateScaleLabel() {

src/sidebar/outline-panel.js

@@ -0,0 +1,114 @@
+/**
+ * Document Outline Panel
+ * Parses markdown headings and renders a navigable tree in the sidebar.
+ */
+
+function renderOutlinePanel(container, { getEditorContent, getActiveLine, onHeadingClick }) {
+    container.innerHTML = `
+        <div class="outline-panel">
+            <div class="outline-list" id="outline-list"></div>
+        </div>
+    `;
+
+    const listEl = document.getElementById('outline-list');
+    let headings = [];
+    let activeLine = 1;
+    let debounceTimer = null;
+
+    function parseHeadings(content) {
+        const result = [];
+        if (!content) return result;
+        const lines = content.split('\n');
+        const regex = /^(#{1,6})\s+(.+)$/;
+        for (let i = 0; i < lines.length; i++) {
+            const match = regex.exec(lines[i]);
+            if (match) {
+                result.push({
+                    level: match[1].length,
+                    text: match[2].trim(),
+                    line: i + 1
+                });
+            }
+        }
+        return result;
+    }
+
+    function findActiveHeading(currentLine) {
+        let active = null;
+        for (const h of headings) {
+            if (h.line <= currentLine) {
+                active = h;
+            } else {
+                break;
+            }
+        }
+        return active;
+    }
+
+    function renderHeadings() {
+        const content = getEditorContent();
+        headings = parseHeadings(content);
+        activeLine = getActiveLine();
+
+        if (headings.length === 0) {
+            listEl.innerHTML = `
+                <div class="outline-empty">
+                    <p>No headings found</p>
+                    <p class="outline-hint"># Heading 1</p>
+                    <p class="outline-hint">## Heading 2</p>
+                    <p class="outline-hint">### Heading 3</p>
+                </div>
+            `;
+            return;
+        }
+
+        const activeHeading = findActiveHeading(activeLine);
+
+        listEl.innerHTML = headings.map((h, idx) => `
+            <div class="outline-item outline-level-${h.level}${activeHeading && h.line === activeHeading.line ? ' active' : ''}"
+                 data-line="${h.line}" data-index="${idx}">
+                <span class="outline-text">${escapeHtml(h.text)}</span>
+                <span class="outline-badge">H${h.level}</span>
+            </div>
+        `).join('') + `<div class="outline-footer">${headings.length} heading${headings.length !== 1 ? 's' : ''}</div>`;
+
+        listEl.querySelectorAll('.outline-item').forEach(item => {
+            item.addEventListener('click', () => {
+                const line = parseInt(item.dataset.line, 10);
+                onHeadingClick(line);
+            });
+        });
+    }
+
+    function escapeHtml(text) {
+        const div = document.createElement('div');
+        div.textContent = text;
+        return div.innerHTML;
+    }
+
+    function refresh() {
+        clearTimeout(debounceTimer);
+        debounceTimer = setTimeout(renderHeadings, 300);
+    }
+
+    function setActiveHeading(line) {
+        activeLine = line;
+        const activeHeading = findActiveHeading(line);
+
+        listEl.querySelectorAll('.outline-item').forEach(item => {
+            const itemLine = parseInt(item.dataset.line, 10);
+            if (activeHeading && itemLine === activeHeading.line) {
+                item.classList.add('active');
+            } else {
+                item.classList.remove('active');
+            }
+        });
+    }
+
+    container._refreshOutline = refresh;
+    container._setActiveHeading = setActiveHeading;
+
+    renderHeadings();
+}
+
+module.exports = { renderOutlinePanel };

src/styles-concreteinfo.css

@@ -1,7 +1,7 @@
 /**
  * ConcreteInfo Theme for MarkdownConverter
  * Based on logo palette: #464646, #9a9696, #e5461f, #e3e3e3, #0d0b09
- * Version: 3.0.0
+ * Version: 4.1.0
  */
 
 /* ============================================

src/styles-modern.css

@@ -16,6 +16,12 @@
   --accent-purple: #8b5cf6;
   --accent-pink: #ec4899;
 
+  /* Semantic Colors */
+  --success: #10b981;
+  --warning: #f59e0b;
+  --error: #ef4444;
+  --info: #3b82f6;
+
   /* Neutral Colors */
   --gray-50: #f9fafb;
   --gray-100: #f3f4f6;
@@ -28,6 +34,19 @@
   --gray-800: #1f2937;
   --gray-900: #111827;
 
+  /* Semantic UI Colors (Light Theme Default) */
+  --text-primary: #1f2937;
+  --text-secondary: #6b7280;
+  --text-muted: #9ca3af;
+  --bg-primary: #ffffff;
+  --bg-secondary: #f9fafb;
+  --bg-tertiary: #f3f4f6;
+  --border-color: #e5e7eb;
+  --border-color-strong: #d1d5db;
+  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
+  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
+  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
+
   /* Glassmorphism */
   --glass-bg: rgba(255, 255, 255, 0.7);
   --glass-border: rgba(255, 255, 255, 0.18);
@@ -39,13 +58,7 @@
   --transition-ease: cubic-bezier(0.4, 0, 0.2, 1);
 }
 
-/* Reset & Base */
-* {
-  margin: 0;
-  padding: 0;
-  box-sizing: border-box;
-}
-
+/* Base styles - Reset is in styles.css */
 body {
   font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
   overflow: hidden;
@@ -2333,3 +2346,29 @@ body[class*="dark"] .breadcrumb-bar {
     font-size: 14px;
     cursor: pointer;
 }
+
+/* Writing Analytics Modal */
+.analytics-overlay { position:fixed; inset:0; background:rgba(0,0,0,0.5); backdrop-filter:blur(4px); display:flex; align-items:center; justify-content:center; z-index:10000; animation:analyticsFadeIn 0.2s ease; }
+.analytics-modal { background:var(--bg-primary,#fff); border-radius:12px; width:520px; max-height:80vh; overflow-y:auto; box-shadow:0 20px 60px rgba(0,0,0,0.3); animation:analyticsSlideUp 0.3s ease; }
+.analytics-header { display:flex; justify-content:space-between; align-items:center; padding:20px 24px; border-bottom:1px solid var(--border-color,#e5e7eb); }
+.analytics-header h2 { margin:0; font-size:18px; font-weight:600; color:var(--text-primary); }
+.analytics-close { background:none; border:none; font-size:24px; cursor:pointer; color:var(--text-muted); padding:4px 8px; border-radius:4px; }
+.analytics-close:hover { background:var(--bg-tertiary); color:var(--text-primary); }
+.analytics-body { padding:16px 24px 24px; }
+.analytics-section { margin-bottom:20px; }
+.analytics-section h3 { font-size:12px; font-weight:600; text-transform:uppercase; letter-spacing:0.05em; color:var(--text-muted,#9ca3af); margin:0 0 10px; }
+.analytics-row { display:flex; justify-content:space-between; align-items:baseline; padding:6px 0; font-size:14px; }
+.analytics-label { color:var(--text-secondary,#6b7280); }
+.analytics-value { font-weight:500; color:var(--text-primary); }
+.analytics-value small { color:var(--text-muted); font-weight:400; margin-left:6px; }
+.readability-meter { height:4px; background:var(--bg-tertiary,#f3f4f6); border-radius:2px; margin-top:8px; overflow:hidden; }
+.readability-fill { height:100%; background:linear-gradient(90deg,#ef4444,#f59e0b,#10b981); border-radius:2px; transition:width 0.5s ease; }
+.word-cloud { display:flex; flex-wrap:wrap; gap:8px; margin-top:8px; }
+.word-tag { background:var(--bg-tertiary,#f3f4f6); padding:4px 10px; border-radius:12px; font-size:13px; color:var(--text-secondary); }
+.word-tag small { opacity:0.5; font-size:10px; margin-left:2px; }
+.analytics-longest { flex-direction:column; gap:4px; }
+.analytics-sentence-preview { font-style:italic; font-size:13px; color:var(--text-secondary); font-weight:400; }
+@keyframes analyticsFadeIn { from{opacity:0} to{opacity:1} }
+@keyframes analyticsSlideUp { from{transform:translateY(16px);opacity:0} to{transform:translateY(0);opacity:1} }
+body[class*="dark"] .analytics-modal { background:var(--gray-800,#1f2937); }
+body[class*="dark"] .word-tag { background:var(--gray-700,#374151); }

src/styles-sidebar.css

@@ -57,6 +57,11 @@
     box-shadow: inset 3px 0 0 var(--primary-dark, #5661b3);
 }
 
+.sidebar-icon:focus-visible {
+    outline: 2px solid var(--primary-dark, #5661b3);
+    outline-offset: 2px;
+}
+
 .sidebar-panel {
     width: 280px;
     background: var(--gray-50, #f9fafb);
@@ -98,6 +103,11 @@
     color: var(--gray-600, #4b5563);
 }
 
+.sidebar-panel-close:focus-visible {
+    outline: 2px solid var(--primary-dark, #5661b3);
+    outline-offset: 2px;
+}
+
 .sidebar-panel-content {
     flex: 1;
     overflow-y: auto;
@@ -266,3 +276,29 @@ body[class*="dark"] .tree-item:hover,
 body[class*="dark"] .git-file:hover {
     background: #333;
 }
+
+/* Outline Panel */
+.outline-panel { display: flex; flex-direction: column; height: 100%; }
+.outline-list { flex: 1; overflow-y: auto; padding: 4px 0; }
+.outline-item { display: flex; align-items: center; justify-content: space-between; padding: 4px 12px; cursor: pointer; font-size: 13px; color: var(--text-secondary, #6b7280); transition: background 0.15s, color 0.15s; border-left: 2px solid transparent; }
+.outline-item:hover { background: var(--bg-tertiary, #f3f4f6); color: var(--text-primary, #1f2937); }
+.outline-item.active { color: var(--accent-blue, #3b82f6); background: rgba(59, 130, 246, 0.08); border-left-color: var(--accent-blue, #3b82f6); font-weight: 600; }
+.outline-level-1 { padding-left: 12px; }
+.outline-level-2 { padding-left: 24px; }
+.outline-level-3 { padding-left: 36px; }
+.outline-level-4 { padding-left: 48px; }
+.outline-level-5 { padding-left: 56px; }
+.outline-level-6 { padding-left: 64px; }
+.outline-text { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
+.outline-badge { font-size: 10px; opacity: 0.5; margin-left: 8px; flex-shrink: 0; }
+.outline-empty { display: flex; flex-direction: column; align-items: center; justify-content: center; padding: 32px 16px; color: var(--text-muted, #9ca3af); text-align: center; }
+.outline-empty p { margin: 4px 0; }
+.outline-hint { font-family: monospace; font-size: 12px; opacity: 0.7; }
+.outline-footer { padding: 8px 12px; border-top: 1px solid var(--border-color, #e5e7eb); font-size: 11px; color: var(--text-muted, #9ca3af); }
+
+/* Outline dark mode */
+body[class*="dark"] .outline-item { color: #9ca3af; }
+body[class*="dark"] .outline-item:hover { background: #374151; color: #e5e7eb; }
+body[class*="dark"] .outline-item.active { color: #8b9aff; background: rgba(139, 154, 255, 0.1); border-left-color: #8b9aff; }
+body[class*="dark"] .outline-empty { color: #6b7280; }
+body[class*="dark"] .outline-footer { border-color: #333; color: #6b7280; }

src/styles-zen.css

@@ -0,0 +1,102 @@
+/* Zen Mode — Distraction-free writing styles */
+
+/* Hide chrome elements */
+body.zen-mode .app-header,
+body.zen-mode .tab-bar,
+body.zen-mode .toolbar,
+body.zen-mode .status-bar,
+body.zen-mode .sidebar,
+body.zen-mode .breadcrumb-bar {
+    display: none !important;
+}
+
+/* Main content fills viewport */
+body.zen-mode .main-content {
+    height: 100vh;
+    overflow: hidden;
+}
+
+/* Editor container takes full width */
+body.zen-mode .editor-container {
+    width: 100% !important;
+    height: 100% !important;
+}
+
+/* Hide preview panes */
+body.zen-mode .preview-container,
+body.zen-mode .preview-pane,
+body.zen-mode .pane-resizer {
+    display: none !important;
+}
+
+/* Center and style editor content for comfortable reading width */
+body.zen-mode .cm-content {
+    max-width: 700px;
+    margin: 0 auto;
+    font-size: 18px;
+    line-height: 1.8;
+    padding-top: 80px;
+}
+
+body.zen-mode .cm-line {
+    padding: 4px 0;
+}
+
+body.zen-mode .editor-wrapper {
+    display: flex;
+    justify-content: center;
+}
+
+/* Floating HUD pill */
+.zen-hud {
+    position: fixed;
+    bottom: 24px;
+    left: 50%;
+    transform: translateX(-50%);
+    background: rgba(0, 0, 0, 0.6);
+    backdrop-filter: blur(12px);
+    -webkit-backdrop-filter: blur(12px);
+    color: rgba(255, 255, 255, 0.8);
+    padding: 10px 24px;
+    border-radius: 24px;
+    font-size: 13px;
+    font-family: 'Plus Jakarta Sans', system-ui, sans-serif;
+    z-index: 9999;
+    pointer-events: none;
+    display: flex;
+    align-items: center;
+    gap: 16px;
+    transition: opacity 0.3s ease;
+}
+
+.zen-hud-stat {
+    opacity: 0.7;
+}
+
+.zen-hud-sep {
+    opacity: 0.3;
+    margin: 0 4px;
+}
+
+/* Word goal progress bar */
+.zen-progress-container {
+    width: 120px;
+    height: 4px;
+    background: rgba(255, 255, 255, 0.15);
+    border-radius: 2px;
+    margin-top: 8px;
+    overflow: hidden;
+    display: none;
+}
+
+.zen-progress-bar {
+    height: 100%;
+    background: rgba(255, 178, 70, 0.85);
+    border-radius: 2px;
+    transition: width 0.3s ease;
+}
+
+/* Dark mode — HUD stays dark in both themes */
+body[class*="dark"].zen-mode .zen-hud {
+    background: rgba(0, 0, 0, 0.7);
+}

src/styles/modal.css

@@ -0,0 +1,265 @@
+/**
+ * Modal System Styles
+ * Unified modal components with glassmorphism backdrop
+ * @version 4.1.0
+ */
+
+/* ============================================
+ * Modal Backdrop - Glassmorphism
+ * ============================================ */
+
+.modal-backdrop {
+    position: fixed;
+    inset: 0;
+    background: rgba(0, 0, 0, 0.4);
+    backdrop-filter: blur(4px);
+    -webkit-backdrop-filter: blur(4px);
+    z-index: 0;
+    cursor: pointer;
+}
+
+/* ============================================
+ * Modal Container
+ * ============================================ */
+
+.modal {
+    position: fixed;
+    inset: 0;
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    z-index: calc(var(--z-modal, 200) + 1);
+    opacity: 0;
+    visibility: hidden;
+    transition: opacity var(--transition-normal, 200ms cubic-bezier(0.4, 0, 0.2, 1)),
+                visibility var(--transition-normal, 200ms cubic-bezier(0.4, 0, 0.2, 1));
+    padding: var(--spacing-4, 1rem);
+}
+
+.modal.open {
+    opacity: 1;
+    visibility: visible;
+}
+
+/* ============================================
+ * Modal Content - With Animation
+ * ============================================ */
+
+.modal-content {
+    position: relative;
+    z-index: 1;
+    width: 100%;
+    background: hsl(var(--background, 0 0% 100%));
+    border-radius: var(--radius-lg, 0.5rem);
+    box-shadow: var(--shadow-xl, 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1));
+    max-width: 90vw;
+    max-height: 90vh;
+    overflow: hidden;
+    display: flex;
+    flex-direction: column;
+    transform: scale(0.95);
+    transition: transform var(--transition-normal, 200ms cubic-bezier(0.4, 0, 0.2, 1));
+}
+
+.modal.open .modal-content {
+    transform: scale(1);
+}
+
+/* ============================================
+ * Modal Header
+ * ============================================ */
+
+.modal-header {
+    display: flex;
+    align-items: center;
+    justify-content: space-between;
+    padding: var(--spacing-4, 1rem) var(--spacing-6, 1.5rem);
+    border-bottom: 1px solid hsl(var(--border, 214.3 31.8% 91.4%));
+    background: hsl(var(--muted, 210 40% 96.1%));
+}
+
+.modal-header h3 {
+    margin: 0;
+    font-size: var(--text-lg, 1.125rem);
+    font-weight: var(--font-semibold, 600);
+    color: hsl(var(--foreground, 222.2 84% 4.9%));
+}
+
+/* ============================================
+ * Modal Close Button
+ * ============================================ */
+
+.modal-close {
+    display: flex;
+    align-items: center;
+    justify-content: center;
+    width: 32px;
+    height: 32px;
+    padding: 0;
+    border: none;
+    border-radius: var(--radius, 0.5rem);
+    background: transparent;
+    color: hsl(var(--muted-foreground, 215.4 16.3% 46.9%));
+    font-size: 24px;
+    line-height: 1;
+    cursor: pointer;
+    transition: background-color var(--transition-fast, 150ms),
+                color var(--transition-fast, 150ms);
+}
+
+.modal-close:hover {
+    background: hsl(var(--accent, 210 40% 96.1%));
+    color: hsl(var(--foreground, 222.2 84% 4.9%));
+}
+
+.modal-close:focus-visible {
+    outline: 2px solid hsl(var(--ring, 227 44% 52%));
+    outline-offset: 2px;
+}
+
+/* ============================================
+ * Modal Body
+ * ============================================ */
+
+.modal-body {
+    padding: var(--spacing-6, 1.5rem);
+    overflow-y: auto;
+    flex: 1;
+}
+
+/* ============================================
+ * Modal Footer
+ * ============================================ */
+
+.modal-footer {
+    display: flex;
+    justify-content: flex-end;
+    gap: var(--spacing-3, 0.75rem);
+    padding: var(--spacing-4, 1rem) var(--spacing-6, 1.5rem);
+    border-top: 1px solid hsl(var(--border, 214.3 31.8% 91.4%));
+    background: hsl(var(--muted, 210 40% 96.1%));
+}
+
+.modal-footer .btn {
+    min-width: 80px;
+    /* styles-modern.css sets flex:1 on .btn-primary/.btn-secondary globally
+     * which causes footer buttons to stretch to full width. Override here. */
+    flex: none;
+}
+
+/* ============================================
+ * Form Elements within Modal
+ * ============================================ */
+
+.modal-body .form-row {
+    display: flex;
+    align-items: center;
+    gap: var(--spacing-3, 0.75rem);
+    margin-bottom: var(--spacing-3, 0.75rem);
+}
+
+.modal-body .form-row label {
+    min-width: 100px;
+    font-size: var(--text-sm, 0.875rem);
+    color: hsl(var(--foreground, 222.2 84% 4.9%));
+}
+
+.modal-body .form-row input,
+.modal-body .form-row select {
+    flex: 1;
+    padding: var(--spacing-2, 0.5rem) var(--spacing-3, 0.75rem);
+    border: 1px solid hsl(var(--input, 214.3 31.8% 91.4%));
+    border-radius: var(--radius, 0.5rem);
+    font-size: var(--text-sm, 0.875rem);
+    background: hsl(var(--background, 0 0% 100%));
+    color: hsl(var(--foreground, 222.2 84% 4.9%));
+}
+
+.modal-body .form-row input:focus,
+.modal-body .form-row select:focus {
+    outline: 2px solid hsl(var(--ring, 227 44% 52%));
+    outline-offset: 1px;
+}
+
+.modal-body .export-section {
+    margin-bottom: var(--spacing-4, 1rem);
+    padding-bottom: var(--spacing-4, 1rem);
+    border-bottom: 1px solid hsl(var(--border, 214.3 31.8% 91.4%));
+}
+
+.modal-body .export-section:last-child {
+    border-bottom: none;
+    margin-bottom: 0;
+}
+
+.modal-body .export-section label {
+    display: block;
+    font-weight: var(--font-medium, 500);
+    margin-bottom: var(--spacing-2, 0.5rem);
+    color: hsl(var(--foreground, 222.2 84% 4.9%));
+}
+
+.modal-body .checkbox-group label {
+    display: flex;
+    align-items: center;
+    gap: var(--spacing-2, 0.5rem);
+    margin-bottom: var(--spacing-2, 0.5rem);
+    font-weight: var(--font-normal, 400);
+    cursor: pointer;
+}
+
+/* ============================================
+ * Size Variants
+ * ============================================ */
+
+.modal-content.small {
+    max-width: 400px;
+    min-width: 320px;
+}
+
+.modal-content.large {
+    max-width: 800px;
+    min-width: 560px;
+}
+
+.modal-content.full {
+    max-width: 95vw;
+    max-height: 95vh;
+    min-width: min(95vw, 700px);
+}
+
+/* ============================================
+ * Dark Mode Support
+ * ============================================ */
+
+.dark .modal-content,
+[data-theme="dark"] .modal-content {
+    background: hsl(var(--background));
+    box-shadow: 0 20px 25px -5px rgb(0 0 0 / 0.4), 0 8px 10px -6px rgb(0 0 0 / 0.3);
+}
+
+.dark .modal-header,
+.dark .modal-footer,
+[data-theme="dark"] .modal-header,
+[data-theme="dark"] .modal-footer {
+    background: hsl(var(--muted));
+}
+
+/* ============================================
+ * Accessibility - Reduced Motion
+ * ============================================ */
+
+@media (prefers-reduced-motion: reduce) {
+    .modal,
+    .modal-content {
+        transition: none;
+    }
+}
+
+/* ============================================
+ * Legacy Support - Hidden class
+ * ============================================ */
+
+.modal.hidden {
+    display: none;
+}

src/styles/tokens.css

@@ -0,0 +1,347 @@
+/**
+ * Design Tokens - Shadcn/ui Compatible
+ *
+ * This file provides CSS custom properties (design tokens) following
+ * the Shadcn/ui convention. These tokens enable consistent theming
+ * and easy theme switching between light and dark modes.
+ *
+ * Usage:
+ *   color: hsl(var(--primary));
+ *   background: hsl(var(--background));
+ *
+ * @version 4.1.0
+ */
+
+:root {
+  /* ============================================
+   * Base Colors - Light Mode
+   * ============================================ */
+
+  /* Background and foreground */
+  --background: 0 0% 100%;
+  --foreground: 222.2 84% 4.9%;
+
+  /* Card */
+  --card: 0 0% 100%;
+  --card-foreground: 222.2 84% 4.9%;
+
+  /* Popover/Dropdown */
+  --popover: 0 0% 100%;
+  --popover-foreground: 222.2 84% 4.9%;
+
+  /* Primary - Brand color (ConcreteInfo blue-purple) */
+  --primary: 227 44% 52%;
+  --primary-foreground: 210 40% 98%;
+
+  /* Secondary */
+  --secondary: 210 40% 96.1%;
+  --secondary-foreground: 222.2 47.4% 11.2%;
+
+  /* Muted - Subtle backgrounds */
+  --muted: 210 40% 96.1%;
+  --muted-foreground: 215.4 16.3% 46.9%;
+
+  /* Accent - Highlight color */
+  --accent: 210 40% 96.1%;
+  --accent-foreground: 222.2 47.4% 11.2%;
+
+  /* Destructive - Error/danger states */
+  --destructive: 0 84.2% 60.2%;
+  --destructive-foreground: 210 40% 98%;
+
+  /* Success - Positive states */
+  --success: 142 76% 36%;
+  --success-foreground: 210 40% 98%;
+
+  /* Warning - Caution states */
+  --warning: 38 92% 50%;
+  --warning-foreground: 0 0% 0%;
+
+  /* Info - Informational states */
+  --info: 199 89% 48%;
+  --info-foreground: 210 40% 98%;
+
+  /* Border and input */
+  --border: 214.3 31.8% 91.4%;
+  --input: 214.3 31.8% 91.4%;
+
+  /* Focus ring */
+  --ring: 227 44% 52%;
+
+  /* ============================================
+   * Spacing & Sizing
+   * ============================================ */
+
+  --radius: 0.5rem;
+  --radius-sm: calc(var(--radius) - 4px);
+  --radius-md: calc(var(--radius) - 2px);
+  --radius-lg: var(--radius);
+  --radius-xl: calc(var(--radius) + 4px);
+
+  /* Spacing unit (4px base) */
+  --spacing-1: 0.25rem;
+  --spacing-2: 0.5rem;
+  --spacing-3: 0.75rem;
+  --spacing-4: 1rem;
+  --spacing-5: 1.25rem;
+  --spacing-6: 1.5rem;
+  --spacing-8: 2rem;
+  --spacing-10: 2.5rem;
+  --spacing-12: 3rem;
+
+  /* ============================================
+   * Typography
+   * ============================================ */
+
+  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
+  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', Monaco, 'Courier New', monospace;
+
+  --text-xs: 0.75rem;
+  --text-sm: 0.875rem;
+  --text-base: 1rem;
+  --text-lg: 1.125rem;
+  --text-xl: 1.25rem;
+  --text-2xl: 1.5rem;
+  --text-3xl: 1.875rem;
+
+  --font-normal: 400;
+  --font-medium: 500;
+  --font-semibold: 600;
+  --font-bold: 700;
+
+  --leading-tight: 1.25;
+  --leading-normal: 1.5;
+  --leading-relaxed: 1.625;
+
+  /* ============================================
+   * Shadows
+   * ============================================ */
+
+  --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
+  --shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
+  --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
+  --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
+  --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
+
+  /* ============================================
+   * Transitions
+   * ============================================ */
+
+  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
+  --transition-normal: 200ms cubic-bezier(0.4, 0, 0.2, 1);
+  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
+
+  /* ============================================
+   * Z-Index Scale
+   * ============================================ */
+
+  --z-dropdown: 50;
+  --z-sticky: 100;
+  --z-modal: 200;
+  --z-popover: 300;
+  --z-tooltip: 400;
+  --z-toast: 500;
+}
+
+/* ============================================
+ * Dark Mode
+ * ============================================ */
+
+.dark,
+[data-theme="dark"] {
+  /* Background and foreground */
+  --background: 222.2 84% 4.9%;
+  --foreground: 210 40% 98%;
+
+  /* Card */
+  --card: 222.2 84% 4.9%;
+  --card-foreground: 210 40% 98%;
+
+  /* Popover/Dropdown */
+  --popover: 222.2 84% 4.9%;
+  --popover-foreground: 210 40% 98%;
+
+  /* Primary */
+  --primary: 227 44% 52%;
+  --primary-foreground: 222.2 47.4% 11.2%;
+
+  /* Secondary */
+  --secondary: 217.2 32.6% 17.5%;
+  --secondary-foreground: 210 40% 98%;
+
+  /* Muted */
+  --muted: 217.2 32.6% 17.5%;
+  --muted-foreground: 215 20.2% 65.1%;
+
+  /* Accent */
+  --accent: 217.2 32.6% 17.5%;
+  --accent-foreground: 210 40% 98%;
+
+  /* Destructive */
+  --destructive: 0 62.8% 30.6%;
+  --destructive-foreground: 210 40% 98%;
+
+  /* Success */
+  --success: 142 76% 26%;
+  --success-foreground: 210 40% 98%;
+
+  /* Warning */
+  --warning: 38 92% 40%;
+  --warning-foreground: 0 0% 100%;
+
+  /* Info */
+  --info: 199 89% 38%;
+  --info-foreground: 210 40% 98%;
+
+  /* Border and input */
+  --border: 217.2 32.6% 17.5%;
+  --input: 217.2 32.6% 17.5%;
+
+  /* Focus ring */
+  --ring: 227 44% 52%;
+}
+
+/* ============================================
+ * Semantic Color Classes
+ * ============================================ */
+
+.bg-background { background-color: hsl(var(--background)); }
+.bg-foreground { background-color: hsl(var(--foreground)); }
+.bg-card { background-color: hsl(var(--card)); }
+.bg-primary { background-color: hsl(var(--primary)); }
+.bg-secondary { background-color: hsl(var(--secondary)); }
+.bg-muted { background-color: hsl(var(--muted)); }
+.bg-accent { background-color: hsl(var(--accent)); }
+.bg-destructive { background-color: hsl(var(--destructive)); }
+
+.text-foreground { color: hsl(var(--foreground)); }
+.text-primary { color: hsl(var(--primary)); }
+.text-secondary { color: hsl(var(--secondary-foreground)); }
+.text-muted-foreground { color: hsl(var(--muted-foreground)); }
+.text-destructive { color: hsl(var(--destructive)); }
+
+.border-border { border-color: hsl(var(--border)); }
+.border-primary { border-color: hsl(var(--primary)); }
+.border-input { border-color: hsl(var(--input)); }
+
+/* ============================================
+ * Utility Classes
+ * ============================================ */
+
+/* Focus ring */
+.focus-ring:focus-visible {
+  outline: 2px solid hsl(var(--ring));
+  outline-offset: 2px;
+}
+
+/* Button base styles */
+.btn {
+  display: inline-flex;
+  align-items: center;
+  justify-content: center;
+  padding: var(--spacing-2) var(--spacing-4);
+  font-size: var(--text-sm);
+  font-weight: var(--font-medium);
+  border-radius: var(--radius);
+  transition: all var(--transition-fast);
+  cursor: pointer;
+}
+
+.btn:focus-visible {
+  outline: 2px solid hsl(var(--ring));
+  outline-offset: 2px;
+}
+
+.btn-primary {
+  background-color: hsl(var(--primary));
+  color: hsl(var(--primary-foreground));
+}
+
+.btn-primary:hover {
+  background-color: hsl(var(--primary) / 0.9);
+}
+
+.btn-secondary {
+  background-color: hsl(var(--secondary));
+  color: hsl(var(--secondary-foreground));
+}
+
+.btn-secondary:hover {
+  background-color: hsl(var(--secondary) / 0.8);
+}
+
+.btn-destructive {
+  background-color: hsl(var(--destructive));
+  color: hsl(var(--destructive-foreground));
+}
+
+.btn-destructive:hover {
+  background-color: hsl(var(--destructive) / 0.9);
+}
+
+.btn-ghost {
+  background-color: transparent;
+  color: hsl(var(--foreground));
+}
+
+.btn-ghost:hover {
+  background-color: hsl(var(--accent));
+}
+
+.btn-outline {
+  background-color: transparent;
+  border: 1px solid hsl(var(--border));
+  color: hsl(var(--foreground));
+}
+
+.btn-outline:hover {
+  background-color: hsl(var(--accent));
+  color: hsl(var(--accent-foreground));
+}
+
+/* Badge styles */
+.badge {
+  display: inline-flex;
+  align-items: center;
+  padding: var(--spacing-1) var(--spacing-2);
+  font-size: var(--text-xs);
+  font-weight: var(--font-medium);
+  border-radius: 9999px;
+}
+
+.badge-primary {
+  background-color: hsl(var(--primary));
+  color: hsl(var(--primary-foreground));
+}
+
+.badge-secondary {
+  background-color: hsl(var(--secondary));
+  color: hsl(var(--secondary-foreground));
+}
+
+.badge-destructive {
+  background-color: hsl(var(--destructive));
+  color: hsl(var(--destructive-foreground));
+}
+
+/* Input styles */
+.input {
+  display: flex;
+  width: 100%;
+  padding: var(--spacing-2) var(--spacing-3);
+  font-size: var(--text-sm);
+  border: 1px solid hsl(var(--input));
+  border-radius: var(--radius);
+  background-color: hsl(var(--background));
+  color: hsl(var(--foreground));
+  transition: border-color var(--transition-fast);
+}
+
+.input:focus-visible {
+  outline: 2px solid hsl(var(--ring));
+  outline-offset: 2px;
+}
+
+.input::placeholder {
+  color: hsl(var(--muted-foreground));
+}

src/utils/ModalManager.js

@@ -0,0 +1,246 @@
+/**
+ * ModalManager - Unified modal system with accessibility support
+ * @version 4.4.1
+ */
+class ModalManager {
+    #modal;
+    #backdrop;
+    #options;
+    #lastFocusedElement;
+    #focusableElements;
+    #eventListeners;
+    #isOpen;
+
+    static #openModals = [];
+
+    constructor(element, options = {}) {
+        this.#modal = typeof element === 'string' ? document.querySelector(element) : element;
+        this.#options = {
+            closeOnBackdrop: true,
+            closeOnEscape: true,
+            focusFirst: true,
+            onOpen: null,
+            onClose: null,
+            ...options
+        };
+        this.#isOpen = false;
+        this.#eventListeners = [];
+        this.#init();
+    }
+
+    #init() {
+        // Ensure modal has required attributes
+        if (!this.#modal.hasAttribute('role')) {
+            this.#modal.setAttribute('role', 'dialog');
+        }
+        if (!this.#modal.hasAttribute('aria-modal')) {
+            this.#modal.setAttribute('aria-modal', 'true');
+        }
+
+        // Find or create backdrop
+        this.#backdrop = this.#modal.querySelector('.modal-backdrop');
+
+        // Setup close triggers
+        this.#setupCloseTriggers();
+    }
+
+    #setupCloseTriggers() {
+        // Close button
+        const closeBtn = this.#modal.querySelector('.modal-close');
+        if (closeBtn) {
+            const handler = (e) => {
+                e.preventDefault();
+                this.close();
+            };
+            closeBtn.addEventListener('click', handler);
+            this.#eventListeners.push({ el: closeBtn, type: 'click', handler });
+        }
+
+        // Elements with data-close attribute
+        const closeTriggers = this.#modal.querySelectorAll('[data-close]');
+        closeTriggers.forEach(el => {
+            if (el.classList.contains('modal-backdrop') && !this.#options.closeOnBackdrop) {
+                return;
+            }
+            const handler = (e) => {
+                e.preventDefault();
+                this.close();
+            };
+            el.addEventListener('click', handler);
+            this.#eventListeners.push({ el, type: 'click', handler });
+        });
+    }
+
+    #getFocusableElements() {
+        const selector = [
+            'button:not([disabled])',
+            'input:not([disabled])',
+            'select:not([disabled])',
+            'textarea:not([disabled])',
+            'a[href]',
+            '[tabindex]:not([tabindex="-1"])'
+        ].join(', ');
+
+        return Array.from(this.#modal.querySelectorAll(selector))
+            .filter(el => el.offsetParent !== null && !el.classList.contains('modal-backdrop'));
+    }
+
+    #trapFocus(e) {
+        if (e.key !== 'Tab') return;
+
+        const focusable = this.#getFocusableElements();
+        if (focusable.length === 0) return;
+
+        const firstEl = focusable[0];
+        const lastEl = focusable[focusable.length - 1];
+
+        if (e.shiftKey) {
+            if (document.activeElement === firstEl) {
+                e.preventDefault();
+                lastEl.focus();
+            }
+        } else {
+            if (document.activeElement === lastEl) {
+                e.preventDefault();
+                firstEl.focus();
+            }
+        }
+    }
+
+    #handleKeydown(e) {
+        if (e.key === 'Escape' && this.#options.closeOnEscape) {
+            e.preventDefault();
+            this.close();
+        }
+        this.#trapFocus(e);
+    }
+
+    open() {
+        if (this.#isOpen) return;
+
+        // Store last focused element
+        this.#lastFocusedElement = document.activeElement;
+
+        // Track open modals
+        ModalManager.#openModals.push(this);
+
+        // Show modal: remove hidden first, force a reflow so the browser
+        // records opacity:0 as the start state, then add 'open' to trigger
+        // the CSS transition. Without the reflow, both class changes are
+        // batched into one style recalculation and the transition is skipped.
+        this.#modal.classList.remove('hidden');
+        void this.#modal.offsetHeight; // Force reflow — do not remove
+        this.#modal.classList.add('open');
+        this.#isOpen = true;
+
+        // Prevent body scroll
+        document.body.style.overflow = 'hidden';
+
+        // Add keyboard listener
+        const keydownHandler = (e) => this.#handleKeydown(e);
+        document.addEventListener('keydown', keydownHandler);
+        this.#eventListeners.push({ el: document, type: 'keydown', handler: keydownHandler });
+
+        // Focus first element
+        if (this.#options.focusFirst) {
+            requestAnimationFrame(() => {
+                const focusable = this.#getFocusableElements();
+                if (focusable.length > 0) {
+                    focusable[0].focus();
+                }
+            });
+        }
+
+        // Callback
+        if (this.#options.onOpen) {
+            this.#options.onOpen(this);
+        }
+
+        // Dispatch custom event
+        this.#modal.dispatchEvent(new CustomEvent('modal:open'));
+    }
+
+    close() {
+        if (!this.#isOpen) return;
+
+        // Remove from open modals
+        const index = ModalManager.#openModals.indexOf(this);
+        if (index > -1) {
+            ModalManager.#openModals.splice(index, 1);
+        }
+
+        // Start hide transition
+        this.#modal.classList.remove('open');
+        this.#isOpen = false;
+
+        // Re-add 'hidden' after the CSS transition completes so the modal
+        // is fully removed from rendering (display:none), not just invisible.
+        // We use both transitionend and a setTimeout fallback because
+        // transitionend never fires when prefers-reduced-motion disables transitions.
+        let hidden = false;
+        const addHidden = () => {
+            if (hidden || this.#isOpen) return;
+            hidden = true;
+            this.#modal.removeEventListener('transitionend', onTransitionEnd);
+            this.#modal.classList.add('hidden');
+        };
+        const onTransitionEnd = (e) => {
+            if (e.target !== this.#modal) return;
+            addHidden();
+        };
+        this.#modal.addEventListener('transitionend', onTransitionEnd);
+        setTimeout(addHidden, 250); // fallback: slightly longer than 200ms transition
+
+        // Restore body scroll if no modals open
+        if (ModalManager.#openModals.length === 0) {
+            document.body.style.overflow = '';
+        }
+
+        // Remove keyboard listener
+        const keydownListener = this.#eventListeners.find(
+            l => l.el === document && l.type === 'keydown'
+        );
+        if (keydownListener) {
+            document.removeEventListener('keydown', keydownListener.handler);
+            this.#eventListeners = this.#eventListeners.filter(l => l !== keydownListener);
+        }
+
+        // Restore focus
+        if (this.#lastFocusedElement && typeof this.#lastFocusedElement.focus === 'function') {
+            this.#lastFocusedElement.focus();
+        }
+
+        // Callback
+        if (this.#options.onClose) {
+            this.#options.onClose(this);
+        }
+
+        // Dispatch custom event
+        this.#modal.dispatchEvent(new CustomEvent('modal:close'));
+    }
+
+    isOpen() {
+        return this.#isOpen;
+    }
+
+    destroy() {
+        // Close if open
+        if (this.#isOpen) {
+            this.close();
+        }
+
+        // Remove all event listeners
+        this.#eventListeners.forEach(({ el, type, handler }) => {
+            el.removeEventListener(type, handler);
+        });
+        this.#eventListeners = [];
+    }
+}
+
+// Export for use in renderer - avoid duplicate declaration
+if (typeof window !== 'undefined' && !window.ModalManager) {
+    window.ModalManager = ModalManager;
+}
+
+// CommonJS export
+module.exports = { ModalManager };

src/welcome.js

@@ -1,4 +1,4 @@
-function createWelcomeContent(recentFiles = []) {
+function createWelcomeContent(recentFiles = [], appVersion = '') {
     const recentHtml = recentFiles.length
         ? recentFiles.map(f => {
             const name = f.split(/[/\\]/).pop();
@@ -10,7 +10,7 @@ function createWelcomeContent(recentFiles = []) {
     <div class="welcome-container">
         <div class="welcome-hero">
             <h1 class="welcome-title">MarkdownConverter</h1>
-            <p class="welcome-version">Version 4.0.0</p>
+            <p class="welcome-version">${appVersion ? `Version ${appVersion}` : ''}</p>
             <p class="welcome-subtitle">Professional Markdown Editor & Universal Document Converter</p>
         </div>
 
@@ -45,7 +45,7 @@ function createWelcomeContent(recentFiles = []) {
             </div>
 
             <div class="welcome-section">
-                <h2>What's New in v4.0.0</h2>
+                <h2>What's New in v4.x</h2>
                 <ul class="welcome-features">
                     <li><strong>CodeMirror Editor</strong> — Syntax highlighting, code folding, multiple cursors</li>
                     <li><strong>Sidebar Panels</strong> — File Explorer, Git, Snippets, Templates</li>

src/zen-mode.js

@@ -0,0 +1,292 @@
+/**
+ * Zen Mode — distraction-free writing mode
+ * Provides typewriter scrolling, line dimming, centered content, and a floating HUD.
+ * Toggle with F11, exit with Escape.
+ */
+
+const {
+    EditorView,
+    ViewPlugin,
+    Decoration,
+    DecorationSet,
+} = require('@codemirror/view');
+const { RangeSetBuilder } = require('@codemirror/state');
+
+class ZenMode {
+    /**
+     * @param {import('./renderer').TabManager} tabManager
+     */
+    constructor(tabManager) {
+        this.tabManager = tabManager;
+        this.active = false;
+        this._hud = null;
+        this._timerInterval = null;
+        this._sessionStart = null;
+        this._extensions = [];
+    }
+
+    activate() {
+        if (this.active) return;
+        this.active = true;
+
+        document.body.classList.add('zen-mode');
+
+        // Collapse sidebar
+        const sidebar = document.getElementById('sidebar');
+        if (sidebar) sidebar.classList.add('collapsed');
+
+        // Hide preview pane for the active tab
+        const tab = this.tabManager.tabs.get(this.tabManager.activeTabId);
+        if (tab) {
+            const previewContainer = document.getElementById(`preview-pane-${tab.id}`);
+            if (previewContainer) previewContainer.classList.add('hidden');
+            const editorPane = document.getElementById(`editor-pane-${tab.id}`);
+            if (editorPane) editorPane.classList.add('full-width');
+
+            // Add CM6 extensions to the active editor
+            if (tab.editorView) {
+                this._extensions = [
+                    typewriterScrollExtension,
+                    lineDimmingExtension,
+                ];
+                // Reconfigure is not straightforward with CM6's immutable state.
+                // Instead we dispatch effects or simply rebuild with new extensions.
+                // Since we cannot hot-swap extensions on an existing EditorView,
+                // we store a reference and the CSS + updateListener handle the rest.
+                // The typewriter + dimming plugins are applied via a compartment approach
+                // would be ideal, but for simplicity we use DOM + updateListener.
+                this._applyTypewriterBehavior(tab.editorView);
+            }
+        }
+
+        // Create HUD
+        this._createHUD();
+
+        // Start session timer
+        this._sessionStart = Date.now();
+        this._timerInterval = setInterval(() => this._updateHUD(), 1000);
+
+        // Focus editor
+        if (tab?.editorView) tab.editorView.focus();
+    }
+
+    deactivate() {
+        if (!this.active) return;
+        this.active = false;
+
+        document.body.classList.remove('zen-mode');
+
+        // Restore preview pane for the active tab
+        const tab = this.tabManager.tabs.get(this.tabManager.activeTabId);
+        if (tab) {
+            const previewContainer = document.getElementById(`preview-pane-${tab.id}`);
+            if (previewContainer) previewContainer.classList.remove('hidden');
+            const editorPane = document.getElementById(`editor-pane-${tab.id}`);
+            if (editorPane) editorPane.classList.remove('full-width');
+
+            // Remove typewriter listener
+            if (tab.editorView && this._selectionListener) {
+                window.removeEventListener('zen-typewriter', this._selectionListener);
+                this._selectionListener = null;
+            }
+        }
+
+        // Remove HUD
+        if (this._hud && this._hud.parentNode) {
+            this._hud.parentNode.removeChild(this._hud);
+            this._hud = null;
+        }
+
+        // Stop timer
+        if (this._timerInterval) {
+            clearInterval(this._timerInterval);
+            this._timerInterval = null;
+        }
+        this._sessionStart = null;
+        this._extensions = [];
+    }
+
+    toggle() {
+        if (this.active) {
+            this.deactivate();
+        } else {
+            this.activate();
+        }
+    }
+
+    _applyTypewriterBehavior(view) {
+        // We use a custom update listener that scrolls the cursor to center.
+        // This is stored on the instance so we can clean it up.
+        let scrollTimeout = null;
+
+        const scrollFn = () => {
+            if (!this.active) return;
+            const pos = view.state.selection.main.head;
+            requestAnimationFrame(() => {
+                view.dispatch({
+                    effects: EditorView.scrollIntoView(pos, { y: 'center' }),
+                });
+            });
+        };
+
+        // Listen for selection/doc changes via a polling approach
+        // since we cannot add extensions to an existing view.
+        // Instead, use the DOM scrollIntoView after selection changes.
+        const observer = new MutationObserver(() => {
+            // No-op, we use interval below
+        });
+
+        // Use interval to keep cursor centered during typing
+        this._scrollInterval = setInterval(() => {
+            if (!this.active) {
+                clearInterval(this._scrollInterval);
+                this._scrollInterval = null;
+                return;
+            }
+            // Typewriter scroll: center the cursor line
+            try {
+                const pos = view.state.selection.main.head;
+                const coords = view.coordsAtPos(pos);
+                const scroller = view.scrollDOM;
+                if (coords && scroller) {
+                    const scrollerRect = scroller.getBoundingClientRect();
+                    const cursorCenter = coords.top + (coords.bottom - coords.top) / 2;
+                    const viewCenter = scrollerRect.top + scrollerRect.height / 2;
+                    const diff = cursorCenter - viewCenter;
+                    if (Math.abs(diff) > 30) {
+                        scroller.scrollTop += diff;
+                    }
+                }
+            } catch (e) {
+                // Ignore errors from destroyed views
+            }
+        }, 200);
+
+        // Initial scroll to center
+        scrollFn();
+    }
+
+    _createHUD() {
+        const hud = document.createElement('div');
+        hud.className = 'zen-hud';
+        hud.innerHTML = `
+            <span class="zen-hud-item" id="zen-words">0 words</span>
+            <span class="zen-hud-sep">&middot;</span>
+            <span class="zen-hud-item" id="zen-reading-time">0 min read</span>
+            <span class="zen-hud-sep">&middot;</span>
+            <span class="zen-hud-item" id="zen-timer">00:00</span>
+            <div class="zen-progress-container" id="zen-progress-container">
+                <div class="zen-progress-bar" id="zen-progress-bar"></div>
+            </div>
+        `;
+        document.body.appendChild(hud);
+        this._hud = hud;
+        this._updateHUD();
+    }
+
+    _updateHUD() {
+        if (!this.active || !this._hud) return;
+
+        const content = this.tabManager.getEditorContent();
+        const words = content.trim() ? content.trim().split(/\s+/).filter(w => w.length > 0).length : 0;
+        const readingTime = Math.max(1, Math.ceil(words / 200));
+
+        const wordsEl = document.getElementById('zen-words');
+        const readingEl = document.getElementById('zen-reading-time');
+        const timerEl = document.getElementById('zen-timer');
+
+        if (wordsEl) wordsEl.textContent = `${words.toLocaleString()} words`;
+        if (readingEl) readingEl.textContent = `${readingTime} min read`;
+
+        // Session timer
+        if (this._sessionStart) {
+            const elapsed = Math.floor((Date.now() - this._sessionStart) / 1000);
+            const minutes = String(Math.floor(elapsed / 60)).padStart(2, '0');
+            const seconds = String(elapsed % 60).padStart(2, '0');
+            if (timerEl) timerEl.textContent = `${minutes}:${seconds}`;
+        }
+
+        // Word goal progress
+        const goalStr = localStorage.getItem('zen-word-goal');
+        const progressBar = document.getElementById('zen-progress-bar');
+        const progressContainer = document.getElementById('zen-progress-container');
+        if (progressBar && progressContainer) {
+            if (goalStr) {
+                const goal = parseInt(goalStr, 10);
+                if (goal > 0) {
+                    const pct = Math.min(100, Math.round((words / goal) * 100));
+                    progressBar.style.width = `${pct}%`;
+                    progressContainer.style.display = 'block';
+                } else {
+                    progressContainer.style.display = 'none';
+                }
+            } else {
+                progressContainer.style.display = 'none';
+            }
+        }
+    }
+}
+
+// Typewriter scroll ViewPlugin
+const typewriterScrollExtension = ViewPlugin.fromClass(class {
+    constructor(view) {
+        this.view = view;
+    }
+
+    update(update) {
+        if (update.selectionSet || update.docChanged) {
+            const pos = update.state.selection.main.head;
+            requestAnimationFrame(() => {
+                if (this.view.dom && this.view.dom.isConnected) {
+                    this.view.dispatch({
+                        effects: EditorView.scrollIntoView(pos, { y: 'center' }),
+                    });
+                }
+            });
+        }
+    }
+});
+
+// Line dimming ViewPlugin
+function getOpacity(distance) {
+    if (distance === 0) return 1.0;
+    if (distance === 1) return 0.7;
+    if (distance === 2) return 0.6;
+    if (distance === 3) return 0.45;
+    return 0.3;
+}
+
+const lineDimmingExtension = ViewPlugin.fromClass(class {
+    constructor(view) {
+        this.decorations = this.buildDecorations(view);
+    }
+
+    update(update) {
+        if (update.docChanged || update.selectionSet || update.viewportChanged) {
+            this.decorations = this.buildDecorations(update.view);
+        }
+    }
+
+    buildDecorations(view) {
+        const builder = new RangeSetBuilder();
+        const pos = view.state.selection.main.head;
+        const activeLine = view.state.doc.lineAt(pos).number;
+        const doc = view.state.doc;
+
+        for (let lineNum = 1; lineNum <= doc.lines; lineNum++) {
+            const line = doc.line(lineNum);
+            const distance = Math.abs(lineNum - activeLine);
+            const opacity = getOpacity(distance);
+            const deco = Decoration.line({
+                attributes: { style: `opacity:${opacity};transition:opacity 0.15s ease` },
+            });
+            builder.add(line.from, line.from, deco);
+        }
+
+        return builder.finish();
+    }
+}, {
+    decorations: v => v.decorations,
+});
+
+module.exports = { ZenMode };

tests/event-bus.test.js

@@ -0,0 +1,64 @@
+const { EventBus } = require('../src/plugins/event-bus');
+
+describe('EventBus', () => {
+  let bus;
+
+  beforeEach(() => {
+    bus = new EventBus();
+  });
+
+  test('on/emit — listener receives payload', () => {
+    const received = [];
+    bus.on('document:saved', (payload) => received.push(payload));
+    bus.emit('document:saved', { filePath: '/test.md', tabId: 'tab1' });
+    expect(received).toEqual([{ filePath: '/test.md', tabId: 'tab1' }]);
+  });
+
+  test('on — ignores events with no listeners', () => {
+    expect(() => bus.emit('unknown:event', {})).not.toThrow();
+  });
+
+  test('off — removes specific listener', () => {
+    const handler = jest.fn();
+    bus.on('test:event', handler);
+    bus.off('test:event', handler);
+    bus.emit('test:event', {});
+    expect(handler).not.toHaveBeenCalled();
+  });
+
+  test('off — removes all listeners for event when no handler given', () => {
+    const h1 = jest.fn();
+    const h2 = jest.fn();
+    bus.on('test:event', h1);
+    bus.on('test:event', h2);
+    bus.off('test:event');
+    bus.emit('test:event', {});
+    expect(h1).not.toHaveBeenCalled();
+    expect(h2).not.toHaveBeenCalled();
+  });
+
+  test('hasHandler — returns true when listener exists', () => {
+    bus.on('ai:analyze', () => {});
+    expect(bus.hasHandler('ai:analyze')).toBe(true);
+  });
+
+  test('hasHandler — returns false when no listener exists', () => {
+    expect(bus.hasHandler('ai:analyze')).toBe(false);
+  });
+
+  test('handler errors are caught and logged, not thrown', () => {
+    const errorSpy = jest.spyOn(console, 'error').mockImplementation(() => {});
+    bus.on('bad:event', () => { throw new Error('boom'); });
+    expect(() => bus.emit('bad:event', {})).not.toThrow();
+    expect(errorSpy).toHaveBeenCalled();
+    errorSpy.mockRestore();
+  });
+
+  test('multiple listeners all receive the event', () => {
+    const results = [];
+    bus.on('multi:event', () => results.push('a'));
+    bus.on('multi:event', () => results.push('b'));
+    bus.emit('multi:event', {});
+    expect(results).toEqual(['a', 'b']);
+  });
+});

tests/git-operations.test.js

@@ -0,0 +1,123 @@
+/**
+ * Git Operations Utilities Test Suite
+ * Tests for async patterns and error handling
+ * @version 4.3.0
+ */
+
+describe('GitOperations Utilities', () => {
+  describe('error handling patterns', () => {
+    it('should handle git errors gracefully', () => {
+      const errorResponse = { error: 'Not a git repository' };
+      
+      expect(errorResponse).toHaveProperty('error');
+      expect(errorResponse.error).toContain('repository');
+    });
+
+    it('should return error object on failure', () => {
+      const failureResult = { error: 'Failed to commit' };
+      
+      expect(failureResult).toBeDefined();
+      expect(failureResult.error).toBeTruthy();
+    });
+  });
+
+  describe('async patterns', () => {
+    it('should handle async operations', async () => {
+      const asyncFn = async () => {
+        return { status: 'success' };
+      };
+
+      const result = await asyncFn();
+      expect(result).toHaveProperty('status');
+    });
+
+    it('should handle async errors', async () => {
+      const asyncFnWithError = async () => {
+        throw new Error('Git operation failed');
+      };
+
+      try {
+        await asyncFnWithError();
+        expect(true).toBe(false); // Should not reach here
+      } catch (err) {
+        expect(err.message).toContain('Git');
+      }
+    });
+  });
+
+  describe('git operations', () => {
+    it('should document expected operations', () => {
+      const gitOps = [
+        'getStatus',
+        'stage',
+        'commit',
+        'log',
+        'diff',
+        'branch',
+        'checkout',
+        'push',
+        'pull'
+      ];
+
+      expect(gitOps.length).toBeGreaterThan(0);
+      gitOps.forEach(op => {
+        expect(typeof op).toBe('string');
+        expect(op.length).toBeGreaterThan(0);
+      });
+    });
+
+    it('should handle directory paths', () => {
+      const paths = [
+        '/home/user/project',
+        './current/dir',
+        '../parent/dir'
+      ];
+
+      paths.forEach(pathStr => {
+        expect(typeof pathStr).toBe('string');
+        expect(pathStr.length).toBeGreaterThan(0);
+      });
+    });
+
+    it('should handle commit messages', () => {
+      const messages = [
+        'fix: bug in git panel',
+        'feat: add new feature',
+        'refactor: clean up code'
+      ];
+
+      messages.forEach(msg => {
+        expect(typeof msg).toBe('string');
+        expect(msg.length).toBeGreaterThan(0);
+      });
+    });
+  });
+
+  describe('response structures', () => {
+    it('should return status info', () => {
+      const statusResponse = {
+        conflicted: [],
+        created: [],
+        deleted: [],
+        modified: [],
+        renamed: [],
+        staged: ['file.md']
+      };
+
+      expect(statusResponse).toHaveProperty('staged');
+      expect(Array.isArray(statusResponse.staged)).toBe(true);
+    });
+
+    it('should return log entries', () => {
+      const logResponse = {
+        all: [
+          { hash: 'abc123', message: 'fix: something' }
+        ],
+        latest: { hash: 'abc123', message: 'fix: something' }
+      };
+
+      expect(logResponse).toHaveProperty('all');
+      expect(Array.isArray(logResponse.all)).toBe(true);
+    });
+  });
+});

tests/goal-tracker.test.js

@@ -0,0 +1,82 @@
+const { GoalTracker } = require('../src/plugins/built-in/writing-studio/goal-tracker');
+
+describe('GoalTracker', () => {
+  let tracker;
+  let store;
+
+  beforeEach(() => {
+    store = {};
+    tracker = new GoalTracker({
+      get: (key) => store[key],
+      set: (key, value) => { store[key] = value; }
+    });
+  });
+
+  test('addWords records words for today', () => {
+    tracker.addWords(500);
+    const today = new Date().toISOString().split('T')[0];
+    expect(store['plugins.writing-studio.history']).toBeDefined();
+    const history = JSON.parse(store['plugins.writing-studio.history']);
+    expect(history[today].words).toBe(500);
+  });
+
+  test('addWords accumulates across multiple calls', () => {
+    tracker.addWords(300);
+    tracker.addWords(200);
+    const today = new Date().toISOString().split('T')[0];
+    const history = JSON.parse(store['plugins.writing-studio.history']);
+    expect(history[today].words).toBe(500);
+  });
+
+  test('getDailyProgress returns 0 when no history', () => {
+    expect(tracker.getDailyProgress(1000)).toEqual({ written: 0, goal: 1000, pct: 0 });
+  });
+
+  test('getDailyProgress returns percentage', () => {
+    tracker.addWords(500);
+    const progress = tracker.getDailyProgress(1000);
+    expect(progress.written).toBe(500);
+    expect(progress.pct).toBe(50);
+  });
+
+  test('getStreak counts consecutive days meeting goal', () => {
+    const today = new Date();
+    for (let i = 0; i < 3; i++) {
+      const d = new Date(today);
+      d.setDate(d.getDate() - i);
+      const key = d.toISOString().split('T')[0];
+      tracker._setHistoryDay(key, { words: 1200 });
+    }
+    const streak = tracker.getStreak(1000);
+    expect(streak).toBe(3);
+  });
+
+  test('getStreak breaks on missed day', () => {
+    const today = new Date();
+    tracker._setHistoryDay(today.toISOString().split('T')[0], { words: 1200 });
+    const yesterday = new Date(today);
+    yesterday.setDate(yesterday.getDate() - 1);
+    tracker._setHistoryDay(yesterday.toISOString().split('T')[0], { words: 500 });
+    const dayBefore = new Date(today);
+    dayBefore.setDate(dayBefore.getDate() - 2);
+    tracker._setHistoryDay(dayBefore.toISOString().split('T')[0], { words: 1200 });
+    expect(tracker.getStreak(1000)).toBe(1);
+  });
+
+  test('getLast30Days returns array of 30 entries', () => {
+    tracker.addWords(100);
+    const days = tracker.getLast30Days();
+    expect(days.length).toBe(30);
+    expect(days[29].words).toBe(100);
+  });
+
+  test('getWeeklyTotal sums last 7 days', () => {
+    const today = new Date();
+    for (let i = 0; i < 7; i++) {
+      const d = new Date(today);
+      d.setDate(d.getDate() - i);
+      tracker._setHistoryDay(d.toISOString().split('T')[0], { words: 200 });
+    }
+    expect(tracker.getWeeklyTotal()).toBe(1400);
+  });
+});

tests/modal-manager.test.js

@@ -0,0 +1,280 @@
+/**
+ * Tests for ModalManager
+ * Covers the three bugs fixed in modal refactor:
+ *   1. open() animation: reflow between hidden removal and open class add
+ *   2. close() cleanup: 'hidden' class restored after transition
+ *   3. State management: isOpen() accuracy
+ */
+
+const { ModalManager } = require('../src/utils/ModalManager');
+
+function createModalElement(id = 'test-modal') {
+    const modal = document.createElement('div');
+    modal.id = id;
+    modal.className = 'modal hidden';
+    modal.setAttribute('role', 'dialog');
+    modal.setAttribute('aria-modal', 'true');
+
+    const backdrop = document.createElement('div');
+    backdrop.className = 'modal-backdrop';
+    backdrop.setAttribute('data-close', '');
+
+    const content = document.createElement('div');
+    content.className = 'modal-content';
+
+    const header = document.createElement('div');
+    header.className = 'modal-header';
+
+    const closeBtn = document.createElement('button');
+    closeBtn.className = 'modal-close';
+    closeBtn.setAttribute('aria-label', 'Close');
+
+    const body = document.createElement('div');
+    body.className = 'modal-body';
+
+    const input = document.createElement('input');
+    input.type = 'text';
+
+    body.appendChild(input);
+    header.appendChild(closeBtn);
+    content.appendChild(header);
+    content.appendChild(body);
+    modal.appendChild(backdrop);
+    modal.appendChild(content);
+    document.body.appendChild(modal);
+
+    return modal;
+}
+
+describe('ModalManager', () => {
+    let modal;
+    let manager;
+
+    beforeEach(() => {
+        modal = createModalElement();
+        manager = new ModalManager(modal);
+    });
+
+    afterEach(() => {
+        manager.destroy();
+        while (document.body.firstChild) {
+            document.body.removeChild(document.body.firstChild);
+        }
+        document.body.style.overflow = '';
+    });
+
+    // =========================================================
+    // open()
+    // =========================================================
+
+    describe('open()', () => {
+        test('removes hidden class and adds open class', () => {
+            expect(modal.classList.contains('hidden')).toBe(true);
+            expect(modal.classList.contains('open')).toBe(false);
+
+            manager.open();
+
+            expect(modal.classList.contains('hidden')).toBe(false);
+            expect(modal.classList.contains('open')).toBe(true);
+        });
+
+        test('sets isOpen to true', () => {
+            expect(manager.isOpen()).toBe(false);
+            manager.open();
+            expect(manager.isOpen()).toBe(true);
+        });
+
+        test('prevents body scroll', () => {
+            manager.open();
+            expect(document.body.style.overflow).toBe('hidden');
+        });
+
+        test('does not open again if already open', () => {
+            manager.open();
+            manager.open(); // second call should be no-op
+            expect(manager.isOpen()).toBe(true);
+        });
+
+        test('calls onOpen callback', () => {
+            const onOpen = jest.fn();
+            manager.destroy();
+            manager = new ModalManager(modal, { onOpen });
+            manager.open();
+            expect(onOpen).toHaveBeenCalledTimes(1);
+        });
+
+        test('dispatches modal:open custom event', () => {
+            const handler = jest.fn();
+            modal.addEventListener('modal:open', handler);
+            manager.open();
+            expect(handler).toHaveBeenCalledTimes(1);
+        });
+    });
+
+    // =========================================================
+    // close()
+    // =========================================================
+
+    describe('close()', () => {
+        beforeEach(() => {
+            manager.open();
+        });
+
+        test('removes open class', () => {
+            expect(modal.classList.contains('open')).toBe(true);
+            manager.close();
+            expect(modal.classList.contains('open')).toBe(false);
+        });
+
+        test('sets isOpen to false immediately', () => {
+            manager.close();
+            expect(manager.isOpen()).toBe(false);
+        });
+
+        test('restores body scroll when no modals remain open', () => {
+            manager.close();
+            expect(document.body.style.overflow).toBe('');
+        });
+
+        test('adds hidden class after transitionend event fires', () => {
+            manager.close();
+
+            // Immediately after close(): hidden should NOT yet be added —
+            // the close animation is still in progress.
+            // (This is the bug that existed before the fix.)
+            expect(modal.classList.contains('hidden')).toBe(false);
+
+            // Simulate the CSS transition completing
+            const event = new Event('transitionend');
+            Object.defineProperty(event, 'target', { value: modal, writable: false });
+            modal.dispatchEvent(event);
+
+            expect(modal.classList.contains('hidden')).toBe(true);
+        });
+
+        test('adds hidden class via 250ms timeout fallback when transitionend never fires', () => {
+            jest.useFakeTimers();
+
+            manager.close();
+            expect(modal.classList.contains('hidden')).toBe(false);
+
+            // Advance past the fallback timeout (250ms)
+            jest.advanceTimersByTime(300);
+
+            expect(modal.classList.contains('hidden')).toBe(true);
+
+            jest.useRealTimers();
+        });
+
+        test('does not add hidden class if modal is reopened before timeout fires', () => {
+            jest.useFakeTimers();
+
+            manager.close();
+            jest.advanceTimersByTime(100); // halfway through timeout
+
+            // Re-open the modal before the timeout fires
+            manager.open();
+
+            jest.advanceTimersByTime(200); // past original timeout expiry
+
+            // Modal was reopened, so hidden must NOT have been added
+            expect(modal.classList.contains('hidden')).toBe(false);
+            expect(modal.classList.contains('open')).toBe(true);
+
+            jest.useRealTimers();
+        });
+
+        test('calls onClose callback', () => {
+            const onClose = jest.fn();
+            manager.destroy();
+            manager = new ModalManager(modal, { onClose });
+            manager.open();
+            manager.close();
+            expect(onClose).toHaveBeenCalledTimes(1);
+        });
+
+        test('dispatches modal:close custom event', () => {
+            const handler = jest.fn();
+            modal.addEventListener('modal:close', handler);
+            manager.close();
+            expect(handler).toHaveBeenCalledTimes(1);
+        });
+
+        test('is a no-op when modal is already closed', () => {
+            manager.close(); // close from open
+            const onClose = jest.fn();
+            manager.destroy();
+            manager = new ModalManager(modal, { onClose });
+            manager.close(); // call close on an already-closed modal
+            expect(onClose).not.toHaveBeenCalled();
+        });
+    });
+
+    // =========================================================
+    // Keyboard interaction
+    // =========================================================
+
+    describe('keyboard shortcuts', () => {
+        test('Escape key closes an open modal', () => {
+            manager.open();
+            document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
+            expect(manager.isOpen()).toBe(false);
+        });
+
+        test('Escape key does nothing when modal is already closed', () => {
+            expect(() => {
+                document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
+            }).not.toThrow();
+        });
+
+        test('closeOnEscape: false prevents Escape from closing', () => {
+            manager.destroy();
+            manager = new ModalManager(modal, { closeOnEscape: false });
+            manager.open();
+            document.dispatchEvent(new KeyboardEvent('keydown', { key: 'Escape', bubbles: true }));
+            expect(manager.isOpen()).toBe(true);
+        });
+    });
+
+    // =========================================================
+    // Close triggers
+    // =========================================================
+
+    describe('close triggers', () => {
+        test('clicking the × close button closes the modal', () => {
+            manager.open();
+            modal.querySelector('.modal-close').click();
+            expect(manager.isOpen()).toBe(false);
+        });
+
+        test('clicking backdrop (data-close) closes the modal', () => {
+            manager.open();
+            modal.querySelector('.modal-backdrop').click();
+            expect(manager.isOpen()).toBe(false);
+        });
+
+        test('closeOnBackdrop: false prevents backdrop from closing', () => {
+            manager.destroy();
+            manager = new ModalManager(modal, { closeOnBackdrop: false });
+            manager.open();
+            modal.querySelector('.modal-backdrop').click();
+            expect(manager.isOpen()).toBe(true);
+        });
+    });
+
+    // =========================================================
+    // destroy()
+    // =========================================================
+
+    describe('destroy()', () => {
+        test('closes modal if open', () => {
+            manager.open();
+            manager.destroy();
+            expect(manager.isOpen()).toBe(false);
+        });
+
+        test('does not throw when destroying a closed modal', () => {
+            expect(() => manager.destroy()).not.toThrow();
+        });
+    });
+});

tests/pdf-operations.test.js

@@ -0,0 +1,95 @@
+/**
+ * PDF Operations Utilities Test Suite
+ * Tests for helper functions and logic patterns
+ * @version 4.3.0
+ */
+
+describe('PDFOperations Utilities', () => {
+  describe('page range parsing', () => {
+    it('should parse single page numbers', () => {
+      // Test logic: parsing "1" should extract page index 0
+      const input = '1';
+      const pages = [0]; // Parsed result
+      
+      expect(pages.length).toBe(1);
+      expect(pages[0]).toBe(0);
+    });
+
+    it('should parse page ranges', () => {
+      // Test logic: parsing "1-3" should extract pages 0, 1, 2
+      const input = '1-3';
+      const pages = [0, 1, 2]; // Expected result
+      
+      expect(pages.length).toBe(3);
+      expect(pages).toEqual([0, 1, 2]);
+    });
+
+    it('should handle multiple ranges', () => {
+      // Test logic: parsing "1-2,4-5" should extract pages 0,1,3,4
+      const input = '1-2,4-5';
+      const pages = [0, 1, 3, 4]; // Expected result
+      
+      expect(pages.length).toBe(4);
+      expect(pages).toEqual([0, 1, 3, 4]);
+    });
+
+    it('should sort pages in ascending order', () => {
+      const unsorted = [2, 0, 3, 1];
+      const sorted = unsorted.sort((a, b) => a - b);
+      
+      expect(sorted).toEqual([0, 1, 2, 3]);
+    });
+  });
+
+  describe('hex color conversion', () => {
+    it('should validate hex color format', () => {
+      const validHex = '#FF5733';
+      const isValid = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.test(validHex);
+      
+      expect(isValid).toBe(true);
+    });
+
+    it('should detect invalid hex colors', () => {
+      const invalidColors = ['#GG5733', '#12345', 'notahex'];
+      
+      invalidColors.forEach(color => {
+        const isValid = /^#?([a-f\d]{2})([a-f\d]{2})([a-f\d]{2})$/i.test(color);
+        expect(isValid).toBe(false);
+      });
+    });
+  });
+
+  describe('error handling', () => {
+    it('should handle empty input', () => {
+      const input = '';
+      expect(input.length).toBe(0);
+      // Should not process empty strings
+      expect(input === '').toBe(true);
+    });
+
+    it('should handle invalid page numbers', () => {
+      const testPages = [
+        { input: '0', isValid: false },
+        { input: '-1', isValid: false },
+        { input: 'abc', isValid: false },
+        { input: '1', isValid: true },
+        { input: '5', isValid: true }
+      ];
+      
+      testPages.forEach(({ input, isValid }) => {
+        const num = parseInt(input);
+        
+        if (isNaN(num)) {
+          // Non-numeric string
+          expect(isValid).toBe(false);
+        } else if (num < 1) {
+          // Zero or negative
+          expect(isValid).toBe(false);
+        } else {
+          // Positive number
+          expect(isValid).toBe(true);
+        }
+      });
+    });
+  });
+});

tests/plugin-api.test.js

@@ -0,0 +1,29 @@
+const { PluginAPI } = require('../src/plugins/plugin-api');
+
+describe('PluginAPI', () => {
+  test('has default no-op lifecycle methods', () => {
+    const plugin = new PluginAPI();
+    expect(() => plugin.init({})).not.toThrow();
+    expect(() => plugin.activate()).not.toThrow();
+    expect(() => plugin.deactivate()).not.toThrow();
+  });
+
+  test('getManifest returns null by default', () => {
+    const plugin = new PluginAPI();
+    expect(plugin.getManifest()).toBeNull();
+  });
+
+  test('subclass can override init', () => {
+    let called = false;
+    class MyPlugin extends PluginAPI {
+      init(context) {
+        called = true;
+        this.context = context;
+      }
+    }
+    const p = new MyPlugin();
+    p.init({ foo: 'bar' });
+    expect(called).toBe(true);
+    expect(p.context.foo).toBe('bar');
+  });
+});

tests/plugin-context.test.js

@@ -0,0 +1,79 @@
+const { PluginContext } = require('../src/plugins/plugin-context');
+const { EventBus } = require('../src/plugins/event-bus');
+
+describe('PluginContext', () => {
+  let context;
+  let mockDeps;
+
+  beforeEach(() => {
+    mockDeps = {
+      pluginId: 'test-plugin',
+      sidebar: { registerPanel: jest.fn() },
+      commands: { register: jest.fn() },
+      statusBar: { registerIndicator: jest.fn() },
+      eventBus: new EventBus(),
+      settings: { get: jest.fn(), set: jest.fn(), onChanged: jest.fn() },
+      editor: { getContent: jest.fn(), getSelection: jest.fn(), insertAtCursor: jest.fn(), onContentChanged: jest.fn() },
+      ipc: { invoke: jest.fn(), on: jest.fn() },
+      exportHooks: { preHooks: [], postHooks: [] }
+    };
+    context = new PluginContext(mockDeps);
+  });
+
+  test('exposes sidebar.registerPanel with namespaced id', () => {
+    const handler = jest.fn();
+    context.sidebar.registerPanel('my-panel', { icon: 'test', title: 'Test', render: handler });
+    expect(mockDeps.sidebar.registerPanel).toHaveBeenCalledWith('test-plugin:my-panel', { icon: 'test', title: 'Test', render: handler });
+  });
+
+  test('exposes commands.register with crash-safe wrapper', () => {
+    const badHandler = () => { throw new Error('boom'); };
+    context.commands.register('bad-cmd', 'Bad', badHandler, 'Ctrl+Alt+T');
+    const registeredHandler = mockDeps.commands.register.mock.calls[0][2];
+    expect(() => registeredHandler()).not.toThrow();
+  });
+
+  test('exposes settings.get/set scoped to plugin', () => {
+    context.settings.get('myKey');
+    context.settings.set('myKey', 'myValue');
+    expect(mockDeps.settings.get).toHaveBeenCalledWith('plugins.test-plugin.myKey');
+    expect(mockDeps.settings.set).toHaveBeenCalledWith('plugins.test-plugin.myKey', 'myValue');
+  });
+
+  test('exposes editor methods', () => {
+    context.editor.getContent();
+    context.editor.getSelection();
+    expect(mockDeps.editor.getContent).toHaveBeenCalled();
+    expect(mockDeps.editor.getSelection).toHaveBeenCalled();
+  });
+
+  test('exposes events via event bus', () => {
+    const handler = jest.fn();
+    context.events.on('test:event', handler);
+    context.events.emit('test:event', { data: 1 });
+    expect(handler).toHaveBeenCalledWith({ data: 1 });
+  });
+
+  test('exposes events.hasHandler', () => {
+    expect(context.events.hasHandler('no:such')).toBe(false);
+    context.events.on('exists:event', () => {});
+    expect(context.events.hasHandler('exists:event')).toBe(true);
+  });
+
+  test('exposes ipc.invoke', () => {
+    context.ipc.invoke('test:channel', { a: 1 });
+    expect(mockDeps.ipc.invoke).toHaveBeenCalledWith('test:channel', { a: 1 });
+  });
+
+  test('exposes exports.registerPreHook', () => {
+    const handler = jest.fn();
+    context.exports.registerPreHook(handler);
+    expect(mockDeps.exportHooks.preHooks).toContain(handler);
+  });
+
+  test('exposes exports.registerPostHook', () => {
+    const handler = jest.fn();
+    context.exports.registerPostHook(handler);
+    expect(mockDeps.exportHooks.postHooks).toContain(handler);
+  });
+});

tests/plugin-loader.test.js

@@ -0,0 +1,102 @@
+const path = require('path');
+const fs = require('fs');
+const os = require('os');
+const { PluginLoader } = require('../src/plugins/plugin-loader');
+
+describe('PluginLoader', () => {
+  let tempDir;
+
+  beforeEach(() => {
+    tempDir = fs.mkdtempSync(path.join(os.tmpdir(), 'plugin-test-'));
+  });
+
+  afterEach(() => {
+    fs.rmSync(tempDir, { recursive: true, force: true });
+  });
+
+  function writeManifest(dir, manifest) {
+    fs.mkdirSync(dir, { recursive: true });
+    fs.writeFileSync(path.join(dir, 'manifest.json'), JSON.stringify(manifest, null, 2));
+  }
+
+  test('discoverPlugins — finds manifests in built-in directory', () => {
+    const pluginDir = path.join(tempDir, 'my-plugin');
+    writeManifest(pluginDir, {
+      id: 'my-plugin',
+      name: 'My Plugin',
+      version: '1.0.0',
+      description: 'Test'
+    });
+    const loader = new PluginLoader([tempDir]);
+    const plugins = loader.discoverPlugins();
+    expect(plugins).toHaveLength(1);
+    expect(plugins[0].id).toBe('my-plugin');
+  });
+
+  test('discoverPlugins — skips directories without manifest.json', () => {
+    const emptyDir = path.join(tempDir, 'no-manifest');
+    fs.mkdirSync(emptyDir, { recursive: true });
+    const loader = new PluginLoader([emptyDir]);
+    const plugins = loader.discoverPlugins();
+    expect(plugins).toHaveLength(0);
+  });
+
+  test('validateManifest — accepts valid manifest', () => {
+    const manifest = {
+      id: 'test-plugin',
+      name: 'Test Plugin',
+      version: '1.0.0',
+      description: 'A test plugin'
+    };
+    const loader = new PluginLoader([]);
+    expect(loader.validateManifest(manifest)).toBe(true);
+  });
+
+  test('validateManifest — rejects manifest missing id', () => {
+    const manifest = { name: 'No ID', version: '1.0.0', description: 'x' };
+    const loader = new PluginLoader([]);
+    expect(() => loader.validateManifest(manifest)).toThrow(/id/);
+  });
+
+  test('validateManifest — rejects manifest missing name', () => {
+    const manifest = { id: 'test', version: '1.0.0', description: 'x' };
+    const loader = new PluginLoader([]);
+    expect(() => loader.validateManifest(manifest)).toThrow(/name/);
+  });
+
+  test('validateManifest — rejects manifest with duplicate id', () => {
+    const loader = new PluginLoader([]);
+    loader.loadedIds = new Set(['existing-plugin']);
+    expect(() => loader.validateManifest({ id: 'existing-plugin', name: 'Dup', version: '1.0.0', description: 'x' }))
+      .toThrow(/duplicate/i);
+  });
+
+  test('discoverPlugins — loads index.js Plugin export if present', () => {
+    const pluginDir = path.join(tempDir, 'with-index');
+    writeManifest(pluginDir, { id: 'with-index', name: 'With Index', version: '1.0.0', description: 'Test' });
+    // Write a simple index.js with a Plugin export
+    fs.writeFileSync(path.join(pluginDir, 'index.js'), `
+class SimplePlugin { init() {} }
+module.exports = { Plugin: SimplePlugin };
+`);
+    const loader = new PluginLoader([tempDir]);
+    const plugins = loader.discoverPlugins();
+    expect(plugins).toHaveLength(1);
+    expect(plugins[0].PluginClass).toBeDefined();
+    expect(plugins[0].PluginClass.name).toBe('SimplePlugin');
+  });
+
+  test('discoverPlugins — continues if one plugin fails to load', () => {
+    const badDir = path.join(tempDir, 'bad');
+    writeManifest(badDir, { id: 'bad', name: 'Bad', version: '1.0.0', description: 'Broken' });
+    fs.writeFileSync(path.join(badDir, 'index.js'), 'throw new Error("broken");');
+
+    const goodDir = path.join(tempDir, 'good');
+    writeManifest(goodDir, { id: 'good', name: 'Good', version: '1.0.0', description: 'Works' });
+
+    const loader = new PluginLoader([tempDir]);
+    const plugins = loader.discoverPlugins();
+    expect(plugins).toHaveLength(1);
+    expect(plugins[0].id).toBe('good');
+  });
+});

tests/plugin-registry.test.js

@@ -0,0 +1,87 @@
+const { PluginRegistry } = require('../src/plugins/plugin-registry');
+const { PluginAPI } = require('../src/plugins/plugin-api');
+const { EventBus } = require('../src/plugins/event-bus');
+
+class TestPlugin extends PluginAPI {
+  init(context) { this.initialized = true; this.ctx = context; }
+  activate() { this.activated = true; }
+  deactivate() { this.deactivated = true; }
+}
+
+describe('PluginRegistry', () => {
+  let registry;
+  let mockDeps;
+
+  beforeEach(() => {
+    mockDeps = {
+      sidebar: { registerPanel: jest.fn() },
+      commands: { register: jest.fn() },
+      statusBar: { registerIndicator: jest.fn() },
+      eventBus: new EventBus(),
+      settings: { get: jest.fn(), set: jest.fn(), onChanged: jest.fn() },
+      editor: { getContent: jest.fn(() => ''), getSelection: jest.fn(() => ''), insertAtCursor: jest.fn(), onContentChanged: jest.fn() },
+      ipc: { invoke: jest.fn(), on: jest.fn() }
+    };
+    registry = new PluginRegistry(mockDeps);
+  });
+
+  test('register — stores plugin and calls init', () => {
+    registry.register({
+      id: 'test', name: 'Test', version: '1.0.0', description: 'desc',
+      manifest: {}, PluginClass: TestPlugin, dir: '/tmp/test'
+    });
+    const entry = registry.getPlugin('test');
+    expect(entry).toBeDefined();
+    expect(entry.instance.initialized).toBe(true);
+  });
+
+  test('register — works without PluginClass', () => {
+    registry.register({
+      id: 'manifest-only', name: 'Manifest Only', version: '1.0.0', description: 'desc',
+      manifest: {}, PluginClass: null, dir: '/tmp/test'
+    });
+    expect(registry.getPlugin('manifest-only')).toBeDefined();
+  });
+
+  test('register — init error does not crash, plugin not registered', () => {
+    class BadPlugin extends PluginAPI {
+      init() { throw new Error('init fail'); }
+    }
+    expect(() => {
+      registry.register({
+        id: 'bad', name: 'Bad', version: '1.0.0', description: 'desc',
+        manifest: {}, PluginClass: BadPlugin, dir: '/tmp/test'
+      });
+    }).not.toThrow();
+    expect(registry.getPlugin('bad')).toBeUndefined();
+  });
+
+  test('getPlugin — returns undefined for unknown', () => {
+    expect(registry.getPlugin('nope')).toBeUndefined();
+  });
+
+  test('getAll — returns all registered plugins', () => {
+    registry.register({ id: 'a', name: 'A', version: '1', description: '', manifest: {}, PluginClass: null, dir: '' });
+    registry.register({ id: 'b', name: 'B', version: '1', description: '', manifest: {}, PluginClass: null, dir: '' });
+    expect(registry.getAll()).toHaveLength(2);
+  });
+
+  test('activate — calls activate on plugin instance', () => {
+    registry.register({ id: 'test', name: 'Test', version: '1', description: '', manifest: {}, PluginClass: TestPlugin, dir: '' });
+    registry.activate('test');
+    expect(registry.getPlugin('test').instance.activated).toBe(true);
+  });
+
+  test('deactivate — calls deactivate on plugin instance', () => {
+    registry.register({ id: 'test', name: 'Test', version: '1', description: '', manifest: {}, PluginClass: TestPlugin, dir: '' });
+    registry.deactivate('test');
+    expect(registry.getPlugin('test').instance.deactivated).toBe(true);
+  });
+
+  test('exportHooks are available and populated', () => {
+    registry.register({ id: 'test', name: 'Test', version: '1', description: '', manifest: {}, PluginClass: TestPlugin, dir: '' });
+    const handler = jest.fn();
+    registry.getPlugin('test').instance.ctx.exports.registerPreHook(handler);
+    expect(registry.exportHooks.preHooks).toContain(handler);
+  });
+});

tests/preload.test.js

@@ -54,6 +54,14 @@ describe('Preload Security', () => {
       'save-pasted-image',
       'load-template',
       'list-directory',
+      'read-file',
+      'write-file',
+      'delete-file',
+      'ensure-directory',
+      'path-exists',
+      'is-directory',
+      'copy-path',
+      'move-path',
       'open-file-path',
       'git-status',
       'git-stage',

tests/project-manager.test.js

@@ -0,0 +1,106 @@
+const { ProjectManager } = require('../src/plugins/built-in/writing-studio/project-manager');
+
+describe('ProjectManager', () => {
+  let pm;
+  let files;
+
+  beforeEach(() => {
+    files = {};
+    pm = new ProjectManager({
+      readFile: (p) => files[p] || null,
+      writeFile: (p, c) => { files[p] = c; },
+      fileExists: (p) => p in files,
+      listDir: (p) => Object.keys(files).filter(f => f.startsWith(p)).map(f => f.slice(p.length + 1))
+    });
+  });
+
+  test('createProject writes .project.json', () => {
+    const project = pm.createProject('/manuscripts/novel', {
+      title: 'My Novel', type: 'manuscript', targetWords: 80000
+    });
+    expect(project.title).toBe('My Novel');
+    expect(files['/manuscripts/novel/.project.json']).toBeDefined();
+    const parsed = JSON.parse(files['/manuscripts/novel/.project.json']);
+    expect(parsed.target.words).toBe(80000);
+  });
+
+  test('loadProject reads and returns project data', () => {
+    files['/manuscripts/novel/.project.json'] = JSON.stringify({
+      title: 'Test', type: 'manuscript', target: { words: 50000 },
+      chapters: [], metadata: {}
+    });
+    const project = pm.loadProject('/manuscripts/novel');
+    expect(project.title).toBe('Test');
+  });
+
+  test('loadProject returns null if no project file', () => {
+    expect(pm.loadProject('/nonexistent')).toBeNull();
+  });
+
+  test('addChapter appends chapter and saves', () => {
+    files['/manuscripts/novel/.project.json'] = JSON.stringify({
+      title: 'Test', type: 'manuscript', target: { words: 50000 },
+      chapters: [], metadata: {}
+    });
+    pm.addChapter('/manuscripts/novel', { file: '01-chapter.md', title: 'Chapter One', status: 'draft' });
+    const parsed = JSON.parse(files['/manuscripts/novel/.project.json']);
+    expect(parsed.chapters.length).toBe(1);
+    expect(parsed.chapters[0].title).toBe('Chapter One');
+  });
+
+  test('compileManuscript concatenates chapter files', () => {
+    files['/manuscripts/novel/.project.json'] = JSON.stringify({
+      title: 'Test', type: 'manuscript', target: { words: 50000 },
+      chapters: [
+        { file: '01.md', title: 'One', status: 'draft' },
+        { file: '02.md', title: 'Two', status: 'draft' }
+      ], metadata: {}
+    });
+    files['/manuscripts/novel/01.md'] = 'First chapter content.';
+    files['/manuscripts/novel/02.md'] = 'Second chapter content.';
+    const result = pm.compileManuscript('/manuscripts/novel');
+    expect(result).toBe('First chapter content.\n\n---\n\nSecond chapter content.');
+  });
+
+  test('compileManuscript skips missing files', () => {
+    files['/manuscripts/novel/.project.json'] = JSON.stringify({
+      title: 'Test', type: 'manuscript', target: { words: 50000 },
+      chapters: [
+        { file: '01.md', title: 'One', status: 'draft' },
+        { file: '02.md', title: 'Two', status: 'draft' }
+      ], metadata: {}
+    });
+    files['/manuscripts/novel/01.md'] = 'Only chapter one.';
+    const result = pm.compileManuscript('/manuscripts/novel');
+    expect(result).toBe('Only chapter one.');
+  });
+
+  test('getStats returns total word count across chapters', () => {
+    files['/manuscripts/novel/.project.json'] = JSON.stringify({
+      title: 'Test', type: 'manuscript', target: { words: 50000 },
+      chapters: [
+        { file: '01.md', title: 'One', status: 'draft' },
+        { file: '02.md', title: 'Two', status: 'draft' }
+      ], metadata: {}
+    });
+    files['/manuscripts/novel/01.md'] = 'word '.repeat(100).trim();
+    files['/manuscripts/novel/02.md'] = 'more '.repeat(50).trim();
+    const stats = pm.getStats('/manuscripts/novel');
+    expect(stats.totalWords).toBeGreaterThan(0);
+    expect(stats.chapterCount).toBe(2);
+    expect(stats.targetWords).toBe(50000);
+    expect(stats.pctComplete).toBeDefined();
+  });
+
+  test('updateChapter modifies a chapter by index', () => {
+    files['/manuscripts/novel/.project.json'] = JSON.stringify({
+      title: 'Test', type: 'manuscript', target: { words: 50000 },
+      chapters: [{ file: '01.md', title: 'Old Title', status: 'draft' }],
+      metadata: {}
+    });
+    pm.updateChapter('/manuscripts/novel', 0, { title: 'New Title', status: 'revised' });
+    const parsed = JSON.parse(files['/manuscripts/novel/.project.json']);
+    expect(parsed.chapters[0].title).toBe('New Title');
+    expect(parsed.chapters[0].status).toBe('revised');
+  });
+});

tests/security-path-handling.test.js

@@ -0,0 +1,114 @@
+/**
+ * Security: Path Traversal Prevention Test Suite
+ * @version 4.3.0
+ */
+
+const path = require('path');
+
+describe('Security: Path Handling', () => {
+  describe('path traversal prevention', () => {
+    it('should detect path traversal patterns', () => {
+      const maliciousPaths = [
+        '../etc/passwd',
+        '../../sensitive',
+        './../outside'
+      ];
+
+      maliciousPaths.forEach(pathStr => {
+        // Path traversal attempts contain .. patterns
+        expect(pathStr).toMatch(/\.\./);
+      });
+    });
+
+    it('should normalize relative paths safely', () => {
+      const safePaths = [
+        './documents/file.md',
+        'relative/path/file.txt'
+      ];
+
+      safePaths.forEach(pathStr => {
+        const normalized = path.normalize(pathStr);
+        // Safe relative paths should normalize cleanly
+        expect(normalized).toBeDefined();
+        expect(typeof normalized).toBe('string');
+      });
+    });
+
+    it('should detect absolute paths', () => {
+      const absolutePath = '/etc/passwd';
+      const isAbsolute = path.isAbsolute(absolutePath);
+      
+      // Linux/Mac: /path is absolute
+      if (process.platform !== 'win32') {
+        expect(isAbsolute).toBe(true);
+      }
+    });
+
+    it('should safely join paths with base directory', () => {
+      const baseDir = '/safe/base/directory';
+      const userInput = 'documents/file.md';
+      
+      const joined = path.join(baseDir, userInput);
+      
+      // Result should contain the safe base
+      expect(joined).toContain('base');
+      expect(joined).toContain('documents');
+    });
+  });
+
+  describe('filename safety', () => {
+    it('should identify safe filenames', () => {
+      const safeNames = [
+        'document.md',
+        'my-file.txt',
+        'file_name.pdf',
+        'report_2026_04_24.xlsx'
+      ];
+
+      safeNames.forEach(name => {
+        // Safe names should not contain path separators or null bytes
+        const isSafe = !/[\\/\0]/.test(name) && name.length > 0;
+        expect(isSafe).toBe(true);
+      });
+    });
+
+    it('should flag filenames with path separators', () => {
+      const problematicNames = [
+        'file/with/slashes.txt',
+        'file\\with\\backslashes.txt'
+      ];
+
+      problematicNames.forEach(name => {
+        // These contain path separators and should be flagged
+        const hasPathSeparators = /[\\/]/.test(name);
+        expect(hasPathSeparators).toBe(true);
+      });
+    });
+
+    it('should enforce minimum filename length', () => {
+      const emptyName = '';
+      
+      expect(emptyName.length).toBe(0);
+      expect(emptyName.length > 0).toBe(false);
+    });
+  });
+
+  describe('validation patterns', () => {
+    it('should validate path existence check pattern', () => {
+      const validationPattern = /^[a-zA-Z0-9._\-/]+$/;
+      
+      const validPaths = ['documents/file.md', 'folder_2026/data.csv'];
+      validPaths.forEach(pathStr => {
+        // These should match a reasonable filename pattern
+        expect(typeof pathStr).toBe('string');
+      });
+    });
+
+    it('should prevent null byte injection', () => {
+      const pathWithNullByte = 'file.txt\0.exe';
+      
+      const isSafe = !pathWithNullByte.includes('\0');
+      expect(isSafe).toBe(false); // Has null byte, not safe
+    });
+  });
+});

tests/settings-store.test.js

@@ -0,0 +1,34 @@
+const { SettingsStore } = require('../src/plugins/settings-store');
+
+describe('SettingsStore', () => {
+  let store;
+  let data;
+
+  beforeEach(() => {
+    data = {};
+    store = new SettingsStore({
+      get: (key) => data[key],
+      set: (key, value) => { data[key] = value; }
+    });
+  });
+
+  test('get returns value for full key', () => {
+    data['plugins.my-plugin.myKey'] = 'myValue';
+    expect(store.get('plugins.my-plugin.myKey')).toBe('myValue');
+  });
+
+  test('get returns undefined for missing key', () => {
+    expect(store.get('plugins.my-plugin.missing')).toBeUndefined();
+  });
+
+  test('set stores value', () => {
+    store.set('plugins.my-plugin.myKey', 42);
+    expect(data['plugins.my-plugin.myKey']).toBe(42);
+  });
+
+  test('set overwrites existing value', () => {
+    data['plugins.my-plugin.myKey'] = 'old';
+    store.set('plugins.my-plugin.myKey', 'new');
+    expect(data['plugins.my-plugin.myKey']).toBe('new');
+  });
+});

tests/setup.js

@@ -17,7 +17,15 @@ global.window.electronAPI = {
     setCurrent: jest.fn(),
     saveRecent: jest.fn(),
     clearRecent: jest.fn(),
-    rendererReady: jest.fn()
+    rendererReady: jest.fn(),
+    read: jest.fn(() => Promise.resolve('')),
+    write: jest.fn(() => Promise.resolve()),
+    delete: jest.fn(() => Promise.resolve()),
+    ensureDir: jest.fn(() => Promise.resolve()),
+    exists: jest.fn(() => Promise.resolve(false)),
+    isDirectory: jest.fn(() => Promise.resolve(false)),
+    copy: jest.fn(() => Promise.resolve()),
+    move: jest.fn(() => Promise.resolve())
   },
   theme: {
     get: jest.fn()

tests/snapshot-manager.test.js

@@ -0,0 +1,73 @@
+const { SnapshotManager } = require('../src/plugins/built-in/writing-studio/snapshot-manager');
+
+describe('SnapshotManager', () => {
+  let manager;
+  let store;
+
+  beforeEach(() => {
+    store = {};
+    manager = new SnapshotManager({
+      get: (key) => store[key],
+      set: (key, value) => { store[key] = value; }
+    });
+  });
+
+  test('create stores snapshot with timestamp, content, wordCount', () => {
+    const snap = manager.create('Hello world this is a test', 'auto');
+    expect(snap).toHaveProperty('id');
+    expect(snap.content).toBe('Hello world this is a test');
+    expect(snap.wordCount).toBe(6);
+    expect(snap.label).toBe('auto');
+  });
+
+  test('list returns snapshots ordered newest first', () => {
+    manager.create('first', 'auto');
+    manager.create('second', 'auto');
+    const list = manager.list();
+    expect(list.length).toBe(2);
+    expect(list[0].content).toBe('second');
+  });
+
+  test('getById returns specific snapshot', () => {
+    const snap = manager.create('find me', 'manual');
+    const found = manager.getById(snap.id);
+    expect(found.content).toBe('find me');
+  });
+
+  test('getById returns null for missing id', () => {
+    expect(manager.getById('nope')).toBeNull();
+  });
+
+  test('restore returns content of snapshot', () => {
+    const snap = manager.create('restore this', 'manual');
+    expect(manager.restore(snap.id)).toBe('restore this');
+  });
+
+  test('restore throws for missing snapshot', () => {
+    expect(() => manager.restore('nope')).toThrow('Snapshot not found');
+  });
+
+  test('delete removes a snapshot', () => {
+    const snap = manager.create('delete me', 'auto');
+    manager.delete(snap.id);
+    expect(manager.getById(snap.id)).toBeNull();
+  });
+
+  test('diff returns added/removed line counts', () => {
+    const snap = manager.create('line one\nline two\nline three', 'auto');
+    const result = manager.diff(snap.id, 'line one\nline modified\nline three\nline four');
+    expect(result.added).toBe(2);
+    expect(result.removed).toBe(1);
+  });
+
+  test('diff throws for missing snapshot', () => {
+    expect(() => manager.diff('nope', 'new content')).toThrow('Snapshot not found');
+  });
+
+  test('prune keeps only the N most recent snapshots', () => {
+    for (let i = 0; i < 10; i++) manager.create('snap ' + i, 'auto');
+    manager.prune(5);
+    expect(manager.list().length).toBe(5);
+    expect(manager.list()[0].content).toBe('snap 9');
+  });
+});

tests/sprint-engine.test.js

@@ -0,0 +1,63 @@
+const { SprintEngine } = require('../src/plugins/built-in/writing-studio/sprint-engine');
+
+describe('SprintEngine', () => {
+  let engine;
+  let events;
+
+  beforeEach(() => {
+    events = [];
+    engine = new SprintEngine({
+      onEvent: (name, data) => events.push({ name, data })
+    });
+  });
+
+  test('starts a sprint with duration and initial word count', () => {
+    engine.start(25, 100);
+    expect(engine.isActive()).toBe(true);
+    expect(engine.getRemaining()).toBeLessThanOrEqual(25 * 60 * 1000);
+  });
+
+  test('start throws if sprint already active', () => {
+    engine.start(25, 100);
+    expect(() => engine.start(10, 50)).toThrow('Sprint already active');
+  });
+
+  test('stop calculates WPM from word delta', () => {
+    engine.start(25, 100);
+    const result = engine.stop(350); // 250 words added
+    expect(result.wordDelta).toBe(250);
+    expect(engine.isActive()).toBe(false);
+  });
+
+  test('stop throws if no active sprint', () => {
+    expect(() => engine.stop(100)).toThrow('No active sprint');
+  });
+
+  test('tick emits progress event with remaining time', () => {
+    engine.start(25, 100);
+    engine.tick(200);
+    expect(events.length).toBe(1);
+    expect(events[0].name).toBe('sprint:tick');
+    expect(events[0].data.remaining).toBeDefined();
+    expect(events[0].data.elapsed).toBe(200);
+  });
+
+  test('tick auto-stops when time expires and emits sprint:complete', () => {
+    engine.start(1, 100); // 1 minute
+    engine.tick(60 * 1000 + 1); // just past
+    expect(events.some(e => e.name === 'sprint:complete')).toBe(true);
+    expect(engine.isActive()).toBe(false);
+  });
+
+  test('getRemaining returns 0 when no sprint active', () => {
+    expect(engine.getRemaining()).toBe(0);
+  });
+
+  test('getStats returns elapsed, WPM, wordDelta after stop', () => {
+    engine.start(25, 100);
+    const result = engine.stop(350);
+    expect(result).toHaveProperty('wordDelta', 250);
+    expect(result).toHaveProperty('elapsed');
+    expect(result).toHaveProperty('wpm');
+  });
+});