Refactored Timer App: Enhance File Handling, Error Handling, and Audio Support
- Added robust error handling for audio file loading and saving, with user notifications via message boxes.
- Switched to JSON for settings storage to manage user preferences (transparency, volume).
- Updated file paths to be relative to the application directory, improving portability.
- Improved initialization of pygame mixer with error handling.
- Implemented dynamic audio file loading from the user selection if no default is found.
- Enhanced transparency control with slider for better UI customization.
- Refined timer logic to handle interruptions and state management more effectively.
- Introduced additional user notifications (warnings and error messages) for better UX.
