tlv84yb7n: Build the sign-in screen and signed-in placeholder shell

src/app/page.tsx

@@ -1,12 +1,5 @@
-// Placeholder home page. The sign-in screen and the feed UI are built in
-// later tasks (tlv84yb7n and the feed tasks). This task delivers the server
-// session routes under /api/session.
+import { App } from "@/components/App";
 
 export default function HomePage() {
-  return (
-    <main style={{ maxWidth: 640, margin: "0 auto", padding: "2rem 1rem" }}>
-      <h1>Minnect feed browser</h1>
-      <p>The sign-in screen is built in a later task.</p>
-    </main>
-  );
+  return <App />;
 }