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/ui/Panel.tsx

@@ -0,0 +1,10 @@
+import type { HTMLAttributes } from "react";
+
+export default function Panel({ className = "", ...props }: HTMLAttributes<HTMLDivElement>) {
+  return (
+    <div
+      className={`rounded-lg border border-chrome/30 bg-ash/80 shadow-lg ${className}`}
+      {...props}
+    />
+  );
+}