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/zod/v3/helpers/errorUtil.d.cts

@@ -0,0 +1,9 @@
+export declare namespace errorUtil {
+    type ErrMessage = string | {
+        message?: string | undefined;
+    };
+    const errToObj: (message?: ErrMessage) => {
+        message?: string | undefined;
+    };
+    const toString: (message?: ErrMessage) => string | undefined;
+}