Migrate to React Router

frontend/src/pages/ProtectedRoute.tsx

@@ -0,0 +1,21 @@
+import { useEffect } from "react";
+import { useAppState } from "./app/ui/state";
+import { useNavigate } from "react-router-dom";
+
+interface ProtectedRouteProps {
+    children: React.ReactNode;
+}
+
+export default function ProtectedRoute({ children }: ProtectedRouteProps) {
+    const { user } = useAppState();
+    const navigate = useNavigate();
+    
+    useEffect(() => {
+        if (!user.authToken) {
+            navigate("/login");
+            return;
+        }
+    }, [user.authToken, user.currentUser, navigate]);
+    
+    return <>{children}</>;
+}