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/@hono/node-server/dist/conninfo.d.mts

@@ -0,0 +1,10 @@
+import { GetConnInfo } from 'hono/conninfo';
+
+/**
+ * ConnInfo Helper for Node.js
+ * @param c Context
+ * @returns ConnInfo
+ */
+declare const getConnInfo: GetConnInfo;
+
+export { getConnInfo };