feat: add Maintenance page, just in case

src/App.tsx

@@ -9,6 +9,16 @@ import { GraphComponent } from "./Network";
 import MVPChart from "./MVPChart";
 import { SetPassword } from "./SetPassword";
 
+const Maintenance = () => {
+  return (
+    <div style={{ textAlign: "center", padding: "20px" }}>
+      <h2>We are under maintenance.</h2>
+      <p>Please check back later. Thank you for your patience.</p>
+      <span style={{ fontSize: "xx-large" }}>🚧</span>
+    </div>
+  );
+};
+
 function App() {
   return (
     <BrowserRouter>