Major Update

### 🚀 New Features

• Path Cleaner: Added a powerful new tool to scan the system PATH variable. It detects and highlights broken paths (directories that no longer exist) and duplicate entries, allowing users to clean them up with a single click.
• Activity History: Introduced a history log window that tracks all user actions (switching versions, adding/deleting entries, exports, etc.) with timestamps for better transparency.
• Import / Export System: Users can now export their complete configuration (groups and versions) to a JSON file and import it on other machines.
• Drag & Drop Support: Added the ability to drag folders directly from Windows Explorer into the application window to automatically fill the "Path" and "Name" fields.
• Live Search: Implemented a real-time search bar to filter the list of versions by name or path.
• Custom Accent Colors: Added a color picker allowing users to customize the application's accent color (default is Orange).
• Group Deletion: Added a trash icon to the group selection dropdown to delete entire language groups.

### 💅 UI/UX Improvements

• Modern Dark Theme: Refined the visual style with a consistent dark theme, rounded corners, and improved spacing.
• Stable Focus: Fixed UI glitches where input fields (like search) would lose focus while typing.
• Responsive Header: Improved the layout of the header controls to prevent wrapping issues on smaller window sizes.

## 🔧 Technical

• Refactoring: Complete code restructuring into modular files (app.rs, logic.rs, style.rs, types.rs, language.rs) for better maintainability and separation of concerns.
• Dependencies: Added chrono for timestamp handling and serde_json for configuration persistence.