Refactor notification progress to use requestAnimationFrame and fix db imports

- Replace CSS animation-based notification progress bar with requestAnimationFrame-driven animation
- Centralize getCanvasState/setCanvasState imports at top-level in CanvasView (remove dynamic import())
- Clean up animation frame lifecycle tracking to prevent orphaned rAF callbacks
- Set local debug log level in python/config.py for development diagnostics

python/config.py

@@ -1,3 +1,3 @@
 # Log level for development.
 # Possible values: 'DEBUG', 'INFO', 'WARN', 'ERROR', 'NONE'
-LOG_LEVEL = 'NONE'
+LOG_LEVEL = 'DEBUG'