- Remove buggy Undo/Redo that saved character-by-character
- Simplify state to plain useState like Google Keep
- Create toast component with success/error/warning/info types
- Toast notifications auto-dismiss after 3s with smooth animations
- Add ToastProvider in layout
- Remove all JavaScript alert() calls
- Production-ready notification system
- Add debounced state updates for title and content (500ms delay)
- Immediate UI updates with delayed history saving
- Prevent one-letter-per-undo issue
- Add cleanup for debounce timers on unmount