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/prisma/build/public/assets/hamburger.5fdadeac.svg

@@ -0,0 +1,4 @@
+<svg viewBox="0 0 24 24" xmlns="http://www.w3.org/2000/svg">
+    <path opacity="0.5" fill-rule="evenodd" clip-rule="evenodd" d="M24 10H0V6H24V10Z" fill="currentColor" />
+    <path opacity="0.5" fill-rule="evenodd" clip-rule="evenodd" d="M24 18H0V14H24V18Z" fill="currentColor" />
+</svg>