Release v3.0.0: PDF Viewer & Editor Integration

Major Features:
- Integrated PDF viewer with zoom, page navigation, and fit modes
- PDF editor toolbar with direct access to all PDF operations
- New app branding with docico1.png icon
- ConcreteInfo theme (light & dark variants)
- Comprehensive PDF editing: merge, split, compress, rotate, delete, reorder
- Watermark, encrypt, decrypt, and permissions management
- Overwrite original file option for all PDF operations

UI Improvements:
- PDF viewer takes full screen when active (hides tabs and toolbar)
- Compact modals with reduced font sizes
- Dark theme fixes for icons and dialogs
- Save/Save As options for PDF operations
- Improved PDF toolbar theming

Technical:
- Added isPdfViewerActive state tracking
- Proper PDF document lifecycle management
- Fixed hang issues when switching between PDF and markdown
- All dependencies are open-source (MIT, Apache 2.0, BSD)

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

eslint.config.js

@@ -0,0 +1,89 @@
+/**
+ * ESLint Configuration for PanConverter
+ * Uses flat config format (ESLint 9+)
+ */
+
+module.exports = [
+  {
+    // Global ignores
+    ignores: [
+      'node_modules/**',
+      'dist/**',
+      'coverage/**',
+      '*.min.js'
+    ]
+  },
+  {
+    // JavaScript files
+    files: ['**/*.js'],
+    languageOptions: {
+      ecmaVersion: 2022,
+      sourceType: 'module',
+      globals: {
+        // Node.js
+        require: 'readonly',
+        module: 'readonly',
+        exports: 'readonly',
+        __dirname: 'readonly',
+        __filename: 'readonly',
+        process: 'readonly',
+        Buffer: 'readonly',
+        console: 'readonly',
+        setTimeout: 'readonly',
+        setInterval: 'readonly',
+        clearTimeout: 'readonly',
+        clearInterval: 'readonly',
+        // Browser
+        window: 'readonly',
+        document: 'readonly',
+        localStorage: 'readonly',
+        alert: 'readonly',
+        Event: 'readonly',
+        CustomEvent: 'readonly',
+        HTMLElement: 'readonly',
+        MutationObserver: 'readonly',
+        // Electron
+        electronAPI: 'readonly',
+        // Libraries
+        marked: 'readonly',
+        DOMPurify: 'readonly',
+        hljs: 'readonly',
+        mermaid: 'readonly',
+        // Jest
+        jest: 'readonly',
+        describe: 'readonly',
+        test: 'readonly',
+        expect: 'readonly',
+        beforeEach: 'readonly',
+        afterEach: 'readonly',
+        beforeAll: 'readonly',
+        afterAll: 'readonly'
+      }
+    },
+    rules: {
+      // Error prevention
+      'no-unused-vars': ['warn', { argsIgnorePattern: '^_' }],
+      'no-undef': 'error',
+      'no-console': 'off', // Allow console for Electron apps
+
+      // Code quality
+      'eqeqeq': ['warn', 'always'],
+      'no-var': 'warn',
+      'prefer-const': 'warn',
+
+      // Style (handled by Prettier)
+      'semi': 'off',
+      'quotes': 'off',
+      'indent': 'off',
+
+      // Async handling
+      'no-async-promise-executor': 'warn',
+      'require-await': 'off',
+
+      // Security
+      'no-eval': 'error',
+      'no-implied-eval': 'error',
+      'no-new-func': 'error'
+    }
+  }
+];