Add comprehensive video playback optimization for smooth performance

Environment variable optimizations:
- KIVY_WINDOW='pygame' - Better window backend performance
- KIVY_AUDIO='ffpyplayer' - Optimized audio playback
- KIVY_GL_BACKEND='gl' - Use OpenGL for better graphics
- FFMPEG_THREADS='4' - Multi-threaded video decoding
- LIBPLAYER_BUFFER='2048000' - 2MB buffer for smooth playback
- SDL_AUDIODRIVER='alsa' - Better audio on Raspberry Pi

Kivy configuration optimizations:
- multisampling=0 - Disable for better performance
- fast_rgba=1 - Enable fast RGBA mode
- Stereo audio (channels=2)
- Reduced logging overhead (warning level)

Video widget enhancements:
- FFmpeg buffer optimization (2MB)
- Multi-threaded decoding (4 threads)
- Ignore index for better seeking
- Allow codec fallback
- 60 FPS animation delay

New video optimization script (.video-optimization.sh):
- GPU memory increased to 256MB
- Install video codec libraries
- Optimize swappiness to 30 (better memory management)
- CPU forced to performance mode
- Filesystem cache optimization

Installation integration:
- Runs video optimization automatically on Raspberry Pi
- Configures GPU memory, libraries, and system settings
- Improves overall video playback smoothness

This addresses video stuttering, frame drops, and playback lag
by optimizing at multiple levels: environment, application, and system.

install.sh

@@ -593,6 +593,19 @@ if detect_raspberry_pi; then
     setup_raspberry_pi_power_management
 fi
 
+# Optimize video playback for Raspberry Pi
+if detect_raspberry_pi; then
+    echo ""
+    echo "=========================================="
+    echo "Optimizing for Video Playback"
+    echo "=========================================="
+    
+    # Run video optimization script
+    if [ -f "$SCRIPT_DIR/.video-optimization.sh" ]; then
+        bash "$SCRIPT_DIR/.video-optimization.sh"
+    fi
+fi
+
 echo "To run the signage player:"
 echo "  cd src && python3 main.py"
 echo ""