Changes:
- Implement async/await pattern for non-blocking server communications
- Use asyncio event loop integrated with Kivy for smooth UI
- Run playlist updates and feedback sending in thread pool
- Prevent UI freezing during network I/O operations
- Add video error handling and playback state management
- Implement delayed video playback start (wait 0.5s for loading)
- Add video error callback for better error recovery
- Cancel all async tasks on application shutdown
- Process async tasks every 100ms without blocking Kivy event loop
New file:
- convert_video_for_rpi.sh: FFmpeg script for optimizing videos (1080p @ 30fps, H.264)
