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/iconv-lite/lib/helpers/merge-exports.js

@@ -0,0 +1,13 @@
+"use strict"
+
+var hasOwn = typeof Object.hasOwn === "undefined" ? Function.call.bind(Object.prototype.hasOwnProperty) : Object.hasOwn
+
+function mergeModules (target, module) {
+  for (var key in module) {
+    if (hasOwn(module, key)) {
+      target[key] = module[key]
+    }
+  }
+}
+
+module.exports = mergeModules