fix: Add debounced Undo/Redo system to avoid character-by-character history

- 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

mcp-server/node_modules/eventsource-parser/src/index.ts

@@ -0,0 +1,3 @@
+export {type ErrorType, ParseError} from './errors.ts'
+export {createParser} from './parse.ts'
+export type {EventSourceMessage, EventSourceParser, ParserCallbacks} from './types.ts'