add old frontend code back

frontend/src/layouts/MainLayout.tsx

@@ -0,0 +1,14 @@
+// layout/MainLayout.jsx
+import Sidebar from '../components/Sidebar'
+import { Outlet } from 'react-router-dom';
+
+const MainLayout = () => (
+    <div className="flex">
+        <Sidebar />
+        <div className="flex-1 p-4">
+            <Outlet /> {/* This renders the nested route content */}
+        </div>
+    </div>
+);
+
+export default MainLayout;