feat: add MainLayout with sidebar

client/src/App.tsx

@@ -1,7 +1,21 @@
 import React from 'react';
+import { Route, Routes } from 'react-router-dom';
+import MainLayout from './pages/MainLayout';
+import ProtectedRoute from './pages/ProtectedRoute';
 
 function App() {
-  return <div className="App"></div>;
+  return (
+    <div className="App">
+      <div>
+        <Routes>
+          <Route path="/login" element={<div>login</div>} />
+          <Route element={<ProtectedRoute />}>
+            <Route path="*" element={<MainLayout />}></Route>
+          </Route>
+        </Routes>
+      </div>
+    </div>
+  );
 }
 
 export default App;