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

components/RegisterServiceWorker.tsx

@@ -0,0 +1,14 @@
+"use client";
+
+import { useEffect } from "react";
+
+export default function RegisterServiceWorker() {
+  useEffect(() => {
+    if (!("serviceWorker" in navigator)) return;
+    navigator.serviceWorker.register("/sw.js").catch((err) => {
+      console.error("Service worker registration failed:", err);
+    });
+  }, []);
+
+  return null;
+}