Add vpinball: a browser Visual Pinball player

Next.js app that plays real .vpx tables via @valknar/vpinball-wasm
(WebAssembly Visual Pinball). Demo mode with the bundled default
table, drag-and-drop custom table upload, a cabinet-styled UI with a
coin-door HUD (fullscreen/stats/info/eject), a custom 404 page, PWA
support (hand-rolled service worker), and a static Docker Compose
deployment behind nginx.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_012hQoM3jJT1Lx7CMTciMzvD

app/not-found.tsx

@@ -0,0 +1,19 @@
+import Link from "next/link";
+import { buttonClassName } from "@/components/ui/Button";
+
+export default function NotFound() {
+  return (
+    <main className="flex flex-1 flex-col items-center justify-center gap-6 px-4 py-24 text-center">
+      <p className="font-mono text-sm tracking-[0.3em] text-arc">TILT</p>
+      <h1 className="font-display text-5xl font-black tracking-wide text-marquee sm:text-7xl">
+        TABLE NOT FOUND
+      </h1>
+      <p className="max-w-md font-body text-chrome">
+        That page drained down the outlane. Head back to the cabinet and pick a table.
+      </p>
+      <Link href="/" className={buttonClassName("primary")}>
+        Back to Start
+      </Link>
+    </main>
+  );
+}