docs(claude-md): add tailored CLAUDE.md for master branch

Documents project architecture, Pandoc dependency resolution, build
pipeline (electron-builder, no bundler), security model notes
(contextIsolation: false on this branch), and development commands
extracted from actual package.json and source.

Amit Haridas

CLAUDE.md

@@ -0,0 +1,103 @@
+# CLAUDE.md — MarkdownConverter (master)
+
+> General code-quality, JavaScript, git, security, and testing standards are in the **global CLAUDE.md**. This file holds project- and branch-specific notes.
+
+## Project Overview
+
+Electron desktop app for Markdown editing and universal file conversion powered by Pandoc. Cross-platform (Win/macOS/Linux). Features: multi-tab editor with live preview, 25+ themes, PDF viewer/editor (merge/split/compress/rotate/watermark/password), export to 20+ formats (PDF/DOCX/ODT/EPUB/HTML/LaTeX/RTF/PPTX), batch conversion, syntax highlighting, diagram support (Mermaid), Git integration, and a plugin system.
+
+- **Version:** 4.4.3
+- **License:** MIT
+- **App ID:** `com.concreteinfo.markdownconverter`
+
+## Branch Specifics
+
+This is the **primary/release branch** — a vanilla JavaScript Electron app with no bundler or framework in the renderer. The renderer is a single large `renderer.js` (5,300+ lines) loaded directly via `src/index.html`. All UI is hand-rolled DOM manipulation.
+
+## Architecture
+
+### Main Process (`src/main.js` — 4,260 lines)
+Monolithic main process file. Contains all IPC handlers, Pandoc invocation, file operations, menu definitions (600+ lines), and window lifecycle. Key modules extracted:
+- `src/main/PDFOperations.js` — PDF manipulation via `pdf-lib` (merge, split, compress, rotate, delete, reorder, watermark, encrypt, decrypt, permissions)
+- `src/main/GitOperations.js` — Git status/stage/commit/log via `simple-git`
+
+### Renderer (`src/renderer.js` — 5,361 lines)
+Vanilla JS, no framework. Directly manipulates DOM. Loads CodeMirror 6 via `src/editor/codemirror-setup.js`. Uses `marked` + `highlight.js` + `DOMPurify` + `mermaid` for rendering. Lazy-loads sidebar panels, REPL, command palette, zen mode.
+
+### Preload (`src/preload.js` — 448 lines)
+Exists as IPC bridge, but **`contextIsolation: false` and `nodeIntegration: true`** — the renderer has full Node access. Preload is effectively a thin passthrough.
+
+### Security Model
+- `contextIsolation: false` + `nodeIntegration: true` (legacy; the react-electron branch fixes this)
+- Pandoc invoked via `execFile` (not `exec`) to prevent shell injection
+- Path traversal protection: `validatePath()`, `resolveWritablePath()`, blocks sensitive system dirs
+- Permission handler only allows `clipboard-read`/`clipboard-write`
+- Rate limiter on conversions (2-second minimum interval)
+- File size limit: 50MB
+- Error message sanitization strips absolute paths
+
+### Plugin System (`src/plugins/`)
+Manifest-based discovery (`manifest.json`). Built-in `writing-studio` plugin with sprint/goal/snapshot management. Plugin API exposed via `src/plugins/plugin-api.js`.
+
+### Settings
+Custom JSON file store at `<userData>/settings.json` (NOT `electron-store` despite the dependency). Recent files at `<userData>/recent-files.json`.
+
+## System Dependencies
+
+| Dependency | Required | Notes |
+|---|---|---|
+| **Node.js** | >= 20 | Electron 41 bundles Node 20.x |
+| **Pandoc** | Yes (for exports) | Downloaded to `bin/<platform>/pandoc` via `scripts/download-tools.js` (v3.9.0.2). Falls back to system PATH. Must be present for DOCX/ODT/EPUB/LaTeX/PPTX export. |
+| **FFmpeg** | Bundled | `ffmpeg-static` npm package; `asarUnpacked` for packaged builds |
+| **MiKTeX / TeX Live** | Optional | For LaTeX PDF export; MiKTeX PATH injected on Windows automatically |
+| **ImageMagick** | Optional | Linux image conversion; listed as deb dependency |
+| **LibreOffice** | Optional | Enhanced document conversion; listed as deb dependency |
+
+## Development Commands
+
+```bash
+npm start                  # Launch Electron app (dev mode)
+npm test                   # Jest test suite
+npm test:watch             # Jest in watch mode
+npm test:coverage          # Jest with coverage report
+npm run lint               # ESLint check (src + tests)
+npm run lint:fix           # ESLint auto-fix
+npm run format             # Prettier write
+npm run format:check       # Prettier check only
+npm run download-tools     # Download Pandoc binaries to bin/
+npm run generate-icons     # Generate app icons via sharp
+```
+
+## Build & Package
+
+**Tool:** `electron-builder` (v26.0.12), config inline in `package.json` (no separate config file).
+
+| Target | Platforms |
+|---|---|
+| `npm run build` | electron-builder (default platform) |
+| `npm run build:win` | Windows: NSIS installer + portable + zip (x64) |
+| `npm run build:mac` | macOS: default dmg |
+| `npm run build:linux` | Linux: deb + AppImage + snap |
+| `npm run dist` | Build without publish |
+| `npm run dist:all` | Build for all platforms |
+
+**Bundled with builds:** Pandoc binary per platform. FFmpeg via `ffmpeg-static` (asarUnpacked). NSIS installer uses custom script at `scripts/nsis-installer.nsh`.
+
+**Output:** `dist/` directory.
+
+**CI:** GitHub Actions workflows in `.github/workflows/` (ci.yml, release.yml).
+
+## Project Conventions / Gotchas
+
+- **No bundler/transpilation.** The app uses vanilla CommonJS JavaScript. `src/main.js` is loaded directly by Electron. No webpack, no Vite, no TypeScript, no Babel.
+- **Monolithic files.** `main.js` (4,260 lines) and `renderer.js` (5,361 lines) contain most logic. Not ideal but is the current state of this branch.
+- **CodeMirror 6** for the editor, configured in `src/editor/codemirror-setup.js`.
+- **PDF rendering** uses `pdfjs-dist`; **PDF manipulation** uses `pdf-lib` in the main process.
+- **Renderer security is weak** — full Node access in renderer. Do NOT introduce new privileged renderer code without understanding this.
+- **Pandoc is external.** Must be installed separately or downloaded via `npm run download-tools`. HTML and built-in PDF export work without Pandoc; other formats require it.
+- **PDF export fallback chain:** xelatex -> pdflatex -> lualatex -> Electron built-in `printToPDF()`.
+- **ESLint flat config** (`eslint.config.js`) with ECMAScript 2022. Prettier with 2-space indent, single quotes, semicolons, 100-char width.
+- **Tests:** Jest with jsdom environment, 15% coverage threshold. 24 test files in `tests/`.
+- **File associations:** `.md`, `.markdown`, `.pdf` registered at install.
+- **Single instance lock** enforced via `app.requestSingleInstanceLock()`.
+- **Adapters layer** (`src/adapters/`) abstracts file system operations for potential future non-Electron targets.

package.json

@@ -1,6 +1,6 @@
 {
   "name": "markdown-converter",
-  "version": "4.4.2",
+  "version": "4.4.3",
   "description": "Professional Markdown editor and universal file converter with PDF editing, batch processing, and syntax highlighting",
   "main": "src/main.js",
   "scripts": {

src/index.html

@@ -4,7 +4,7 @@
     <meta charset="UTF-8">
     <!-- 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' https://cdn.jsdelivr.net; style-src 'self' 'unsafe-inline' https://cdn.jsdelivr.net; img-src 'self' data: blob:; font-src 'self' data: https://cdn.jsdelivr.net; connect-src 'self' https://www.plantuml.com;">
+    <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 -->

src/main.js

@@ -242,9 +242,7 @@ function runPandoc(args, callback) {
 function runPandocCmd(cmdString, callback) {
   const parsed = parseCommand(cmdString);
   // Skip 'pandoc' if it's the first element (command itself)
-  // Use path.basename to handle full paths like bin/linux/pandoc
+  const args = parsed.command === 'pandoc' ? parsed.args : [parsed.command, ...parsed.args];
-  const cmdBase = path.basename(parsed.command).replace(/\.exe$/i, '');
-  const args = cmdBase === 'pandoc' ? parsed.args : [parsed.command, ...parsed.args];
   const pandocPath = getPandocPath();
   execFile(pandocPath, args, { maxBuffer: 10 * 1024 * 1024 }, callback);
 }

src/renderer.js

@@ -1,20 +1,9 @@
 /**
  * MarkdownConverter Renderer Process
- * @version 4.4.2
+ * @version 4.4.3
  */
 
 const { ipcRenderer } = require('electron');
-
-// Shim window.electronAPI for main window which uses nodeIntegration
-// without preload script (window.electronAPI is normally set by preload.js).
-if (typeof window !== 'undefined' && !window.electronAPI) {
-    window.electronAPI = {
-        getAppVersion: () => ipcRenderer.invoke('get-app-version'),
-        invoke: (channel, data) => ipcRenderer.invoke(channel, data),
-        on: (channel, callback) => ipcRenderer.on(channel, (event, ...args) => callback(...args))
-    };
-}
-
 const marked = require('marked');
 const { markedHighlight } = require('marked-highlight');
 const createDOMPurify = require('dompurify');
@@ -22,12 +11,53 @@ const DOMPurify = createDOMPurify(window);
 const hljs = require('highlight.js');
 const { createEditor } = require('./editor/codemirror-setup');
 const { undo, redo } = require('@codemirror/commands');
-// ModalManager is loaded via <script src="utils/ModalManager.js"> in index.html.
+
-// It already exists in the global scope — re-declaring with let/const causes
+// Define a fallback window.electronAPI object for when contextIsolation is disabled
-// SyntaxError: "Identifier 'ModalManager' has already been declared".
+// and the preload script is not loaded in the main window context.
-if (typeof ModalManager === 'undefined') {
+if (typeof window !== 'undefined' && !window.electronAPI) {
+    window.electronAPI = {
+        send: (channel, data) => {
+            ipcRenderer.send(channel, data);
+        },
+        invoke: async (channel, data) => {
+            return await ipcRenderer.invoke(channel, data);
+        },
+        on: (channel, callback) => {
+            const subscription = (event, ...args) => callback(...args);
+            ipcRenderer.on(channel, subscription);
+            return () => {
+                ipcRenderer.removeListener(channel, subscription);
+            };
+        },
+        once: (channel, callback) => {
+            ipcRenderer.once(channel, (event, ...args) => callback(...args));
+        },
+        removeAllListeners: (channel) => {
+            ipcRenderer.removeAllListeners(channel);
+        },
+        getAppVersion: () => ipcRenderer.invoke('get-app-version'),
+        file: {
+            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 })
+        }
+    };
+}
+
+// Use window.ModalManager if already set by script tag, otherwise require it.
+// This prevents "Identifier 'ModalManager' has already been declared" when
+// both the script tag in index.html and CommonJS require() declare it.
+let _ModalManager;
+if (typeof window !== 'undefined' && window.ModalManager) {
+    _ModalManager = window.ModalManager;
+} else {
     const result = require('./utils/ModalManager');
-    ModalManager = result.ModalManager || result;
+    _ModalManager = result.ModalManager || result;
 }
 // Lazy-loaded modules — defer heavy imports until first use
 let _SidebarManager, _renderTemplatesPanel, _renderExplorerPanel, _renderGitPanel, _renderSnippetsPanel;
@@ -490,7 +520,38 @@ class TabManager {
         document.querySelector('.editor-container').appendChild(tabContent);
 
         // Initialize CodeMirror editor
-        this.ensureEditor(tab);
+        const editorContainer = document.getElementById(`editor-cm-${tab.id}`);
+        if (editorContainer) {
+            const isDark = document.body.className.includes('dark');
+            tab.editorView = createEditor(editorContainer, {
+                content: tab.content,
+                onChange: (newContent) => {
+                    tab.content = newContent;
+                    tab.isDirty = true;
+                    // Dynamically enable/disable Large File Mode on edit
+                    if (newContent.length > 1024 * 1024) {
+                        if (!tab.largeFileMode) {
+                            tab.largeFileMode = true;
+                            this.isPreviewVisible = false;
+                            this.updatePreviewVisibility();
+                            notifyUser('Large content detected (>1MB). Large File Mode enabled to maintain peak responsiveness. Live preview auto-render is disabled.', 'warning');
+                        }
+                    } else {
+                        tab.largeFileMode = false;
+                    }
+                    this.updatePreview(tab.id);
+                    this.updateWordCount();
+                    this.updateTabBar();
+                    if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
+                },
+                onUpdate: (view) => {
+                    this.updateCursorPosition(view);
+                    if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
+                },
+                isDark,
+                showLineNumbers: this.showLineNumbers,
+            });
+        }
     }
     
     switchToTab(tabId) {
@@ -1461,47 +1522,9 @@ class TabManager {
         return tab?.content || '';
     }
 
-    // Ensure a tab has a CodeMirror editor (lazy creation fallback)
-    ensureEditor(tab) {
-        if (tab.editorView) return true;
-        const editorContainer = document.getElementById(`editor-cm-${tab.id}`);
-        if (!editorContainer) {
-            console.error(`[ensureEditor] editor-cm-${tab.id} not found in DOM`);
-            return false;
-        }
-        try {
-            const isDark = document.body.className.includes('dark');
-            tab.editorView = createEditor(editorContainer, {
-                content: tab.content,
-                onChange: (newContent) => {
-                    tab.content = newContent;
-                    tab.isDirty = true;
-                    this.updatePreview(tab.id);
-                    this.updateWordCount();
-                    this.updateTabBar();
-                    if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
-                },
-                onUpdate: (view) => {
-                    this.updateCursorPosition(view);
-                    if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
-                },
-                isDark,
-                showLineNumbers: this.showLineNumbers,
-            });
-            console.log(`[ensureEditor] Created editor for tab ${tab.id}`);
-            return true;
-        } catch (err) {
-            console.error(`[ensureEditor] Failed to create editor for tab ${tab.id}:`, err);
-            return false;
-        }
-    }
-
     // Set content in editor
     setEditorContent(tabId, content) {
         const tab = this.tabs.get(tabId);
-        if (!tab?.editorView) {
-            this.ensureEditor(tab);
-        }
         if (tab?.editorView) {
             tab.editorView.dispatch({
                 changes: { from: 0, to: tab.editorView.state.doc.length, insert: content }
@@ -1558,6 +1581,7 @@ let tabManager;
 let replPanel;
 
 document.addEventListener('DOMContentLoaded', async () => {
+    const ModalManager = _ModalManager;
     tabManager = new TabManager();
 
     // Load saved Custom Preview CSS if present
@@ -1690,6 +1714,11 @@ document.addEventListener('DOMContentLoaded', async () => {
     });
 
     const statusBarRight = document.querySelector('.status-bar-right');
+
+    // Initialize command palette
+    const CommandPalette = getCommandPalette();
+    const commandPalette = new CommandPalette();
+
     const pluginRegistry = new PluginRegistry({
         sidebar: sidebarManager,
         commands: commandPalette,
@@ -1745,8 +1774,7 @@ document.addEventListener('DOMContentLoaded', async () => {
         const welcomeHtml = getCreateWelcomeContent()(recentFiles, appVersion);
 
         const tab = tabManager.tabs.get(tabManager.activeTabId);
-        // Only show welcome if no file was opened while we were awaiting
+        if (tab) {
-        if (tab && !tab.filePath && tab.content === '') {
             tab.title = 'Welcome';
             tab.content = '';
             const preview = document.getElementById(`preview-${tab.id}`);
@@ -1827,10 +1855,6 @@ document.addEventListener('DOMContentLoaded', async () => {
         }
     });
 
-    // Initialize command palette
-    const CommandPalette = getCommandPalette();
-    const commandPalette = new CommandPalette();
-
     // Initialize print preview
     const PrintPreview = getPrintPreview();
     const printPreview = new PrintPreview();
@@ -1915,9 +1939,27 @@ document.addEventListener('DOMContentLoaded', async () => {
     });
 
     // Initialize CodeMirror for the initial tab (tab 1)
-    const initialTab = tabManager.tabs.get(1);
+    const initialEditorContainer = document.getElementById('editor-cm-1');
-    if (initialTab) {
+    if (initialEditorContainer) {
-        tabManager.ensureEditor(initialTab);
+        const tab = tabManager.tabs.get(1);
+        const isDark = document.body.className.includes('dark');
+        tab.editorView = createEditor(initialEditorContainer, {
+            content: tab.content,
+            onChange: (newContent) => {
+                tab.content = newContent;
+                tab.isDirty = true;
+                tabManager.updatePreview(tab.id);
+                tabManager.updateWordCount();
+                tabManager.updateTabBar();
+                if (outlinePanelContainer?._refreshOutline) outlinePanelContainer._refreshOutline();
+            },
+            onUpdate: (view) => {
+                tabManager.updateCursorPosition(view);
+                if (outlinePanelContainer?._setActiveHeading) outlinePanelContainer._setActiveHeading(view.state.doc.lineAt(view.state.selection.main.head).number);
+            },
+            isDark,
+            showLineNumbers: tabManager.showLineNumbers,
+        });
     }
 
     // Request current theme

src/utils/ModalManager.js

@@ -1,6 +1,6 @@
 /**
  * ModalManager - Unified modal system with accessibility support
- * @version 4.4.2
+ * @version 4.4.3
  */
 class ModalManager {
     #modal;