Fix critical double-click file opening bug (v1.7.4)

CRITICAL BUG FIX: Files opened via double-click were not rendering in the application.

Root Cause:
- The openFileFromPath() function was sending IPC 'file-opened' message WITHOUT checking if rendererReady was true
- When files were double-clicked before renderer initialization, the IPC message was sent but lost
- The comment "Always try to send, the renderer will handle it when ready" was incorrect

The Fix (src/main.js:1586):
- Added rendererReady check to the conditional: if (mainWindow && mainWindow.webContents && rendererReady)
- Now properly stores file in app.pendingFile when renderer is not ready
- File is opened correctly when renderer-ready signal arrives

Flow:
1. File double-clicked → openFileFromPath() called
2. If renderer NOT ready → store in app.pendingFile
3. When renderer sends 'renderer-ready' → openFileFromPath(app.pendingFile) is called
4. This time renderer IS ready → file opens successfully

Version: 1.7.4
- Updated package.json version to 1.7.4
- Updated About dialog version to 1.7.4

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

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "pan-converter",
-  "version": "1.7.3",
+  "version": "1.7.4",
   "description": "Cross-platform Markdown editor and converter using Pandoc",
   "main": "src/main.js",
   "scripts": {

src/main.js

@@ -410,7 +410,7 @@ function createMenu() {
               type: 'info',
               title: 'About PanConverter',
               message: 'PanConverter',
-              detail: 'A cross-platform Markdown editor and converter using Pandoc.\n\nVersion: 1.7.3\nAuthor: Amit Haridas\nEmail: amit.wh@gmail.com\nLicense: MIT\n\nFeatures:\n• Modern glassmorphism UI with gradient backgrounds\n• Comprehensive PDF Editor (merge, split, compress, rotate, watermark, encrypt)\n• Universal File Converter (LibreOffice, ImageMagick, FFmpeg, Pandoc)\n• Windows Explorer context menu integration\n• Tabbed interface for multiple files\n• Advanced markdown editing with live preview\n• Real-time preview updates while typing\n• Full toolbar markdown editing functions\n• Enhanced PDF export with built-in Electron fallback\n• File association support for .md files\n• Command-line interface for batch conversion\n• Advanced export options with templates and metadata\n• Batch file conversion with progress tracking\n• Improved preview typography and spacing\n• Adjustable font sizes via menu (Ctrl+Shift+Plus/Minus)\n• Complete theme support including Monokai fixes\n• Find & replace with match highlighting\n• Line numbers and auto-indentation\n• Export to multiple formats via Pandoc\n• PowerPoint & presentation export\n• Export tables to Excel/ODS spreadsheets\n• Document import & conversion\n• Table creation helper\n• 22 beautiful themes (including Dracula, Nord, Tokyo Night, Gruvbox, Ayu, Concrete, and more)\n• Undo/redo functionality\n• Live word count and statistics',
+              detail: 'A cross-platform Markdown editor and converter using Pandoc.\n\nVersion: 1.7.4\nAuthor: Amit Haridas\nEmail: amit.wh@gmail.com\nLicense: MIT\n\nFeatures:\n• Modern glassmorphism UI with gradient backgrounds\n• Comprehensive PDF Editor (merge, split, compress, rotate, watermark, encrypt)\n• Universal File Converter (LibreOffice, ImageMagick, FFmpeg, Pandoc)\n• Windows Explorer context menu integration\n• Tabbed interface for multiple files\n• Advanced markdown editing with live preview\n• Real-time preview updates while typing\n• Full toolbar markdown editing functions\n• Enhanced PDF export with built-in Electron fallback\n• File association support for .md files\n• Command-line interface for batch conversion\n• Advanced export options with templates and metadata\n• Batch file conversion with progress tracking\n• Improved preview typography and spacing\n• Adjustable font sizes via menu (Ctrl+Shift+Plus/Minus)\n• Complete theme support including Monokai fixes\n• Find & replace with match highlighting\n• Line numbers and auto-indentation\n• Export to multiple formats via Pandoc\n• PowerPoint & presentation export\n• Export tables to Excel/ODS spreadsheets\n• Document import & conversion\n• Table creation helper\n• 22 beautiful themes (including Dracula, Nord, Tokyo Night, Gruvbox, Ayu, Concrete, and more)\n• Undo/redo functionality\n• Live word count and statistics',
               buttons: ['OK']
             });
           }
@@ -1583,12 +1583,12 @@ function openFileFromPath(filePath) {
   if (fs.existsSync(filePath)) {
     currentFile = filePath;
     const content = fs.readFileSync(filePath, 'utf-8');
-    if (mainWindow && mainWindow.webContents) {
-      console.log('Attempting to open file:', filePath, 'rendererReady:', rendererReady);
-      // Always try to send, the renderer will handle it when ready
+    if (mainWindow && mainWindow.webContents && rendererReady) {
+      console.log('Opening file (renderer ready):', filePath);
       mainWindow.webContents.send('file-opened', { path: filePath, content });
     } else {
-      // Store file to open after window is created
+      console.log('Renderer not ready, storing file:', filePath);
+      // Store file to open after renderer is ready
       app.pendingFile = filePath;
     }
   } else {