[Fix] Remove duplicate root page.tsx shadowing public landing

The leftover scaffold stub at src/app/page.tsx was resolving to / and
shadowing the real landing page at src/app/(public)/page.tsx, leaving
the site rendering only the title and tagline.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/app/page.tsx

@@ -1,8 +0,0 @@
-export default function RootPage() {
-  return (
-    <main className="flex min-h-screen flex-col items-center justify-center">
-      <h1 className="text-4xl font-bold">MovieDice</h1>
-      <p className="mt-4 text-lg text-foreground/60">One shared list. One button to decide.</p>
-    </main>
-  );
-}