Restore the app files (prior commit mis-scoped its tar)

Co-Authored-By: Claude Opus 4.8 <[email protected]>

frontend/src/main.tsx

@@ -0,0 +1,16 @@
+import { StrictMode } from 'react';
+import { createRoot } from 'react-dom/client';
+import { BrowserRouter } from 'react-router-dom';
+import App from './App';
+import { AuthProvider } from './lib/auth';
+import './index.css';
+
+createRoot(document.getElementById('root')!).render(
+  <StrictMode>
+    <BrowserRouter>
+      <AuthProvider>
+        <App />
+      </AuthProvider>
+    </BrowserRouter>
+  </StrictMode>,
+);