Fix critical bugs: real-time preview, toolbar functions, and file opening

Version 1.5.7 - Bug Fix Release
Fixed Issues:
- Real-time preview updates: Preview pane now updates instantly while typing
- Toolbar markdown functions: All toolbar buttons now work correctly
  * Bold, Italic, Code, Link text wrapping
  * Heading, List, Quote line prefixes
  * Table insertion
- File opening: Fixed file loading via menu and double-click association
- Cross-platform path handling for Windows backslashes
Technical Changes:
- Added direct input event listeners to editor textareas
- Implemented wrapSelection() and insertAtLineStart() helper methods
- Fixed IPC communication between main and renderer processes
- Improved event delegation for multi-tab support
🤖 Generated with [Claude Code](https://claude.com/claude-code)

README.md

@@ -54,8 +54,8 @@ Download the latest release for your platform from the [Releases](https://github
 
 #### Linux
 - **AppImage**: `PanConverter-1.5.0.AppImage` (universal, may require `--no-sandbox` flag)
-- **Debian Package**: `pan-converter_1.5.0_amd64.deb`
-- **Snap Package**: `pan-converter_1.5.0_amd64.snap`
+- **Debian Package**: `pan-converter_1.5.6_amd64.deb`
+- **Snap Package**: `pan-converter_1.5.6_amd64.snap`
 
 ### Install from Source
 ```bash
@@ -138,6 +138,8 @@ npm run dist:all
 
 ## Version History
 
+- **v1.5.6** - (Your release notes here)
+- **v1.5.5** - Refactored PDF export, simplified Pandoc pathing, and removed XLSX dependency.
 - **v1.3.1** - Bug fixes: Fixed file associations for double-clicking .md files, corrected 50/50 layout alignment for editor/preview panes
 - **v1.3.0** - Major update: Tabbed interface for multiple files, enhanced PDF export with LaTeX engines, fixed file associations, removed redundant converter menu, improved UI architecture
 - **v1.2.1** - Comprehensive editor enhancements: Find & Replace, Line Numbers, Undo/Redo, Auto-indentation, PowerPoint export, document conversion menu, table creation helper, spreadsheet export