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/hud/useIdleTimer.ts

@@ -0,0 +1,33 @@
+"use client";
+
+import { useEffect, useRef, useState } from "react";
+
+/** True once no pointer/keyboard activity has been seen for `timeoutMs`. */
+export function useIdleTimer(timeoutMs = 3000): boolean {
+  const [isIdle, setIsIdle] = useState(false);
+  const timerRef = useRef<ReturnType<typeof setTimeout> | null>(null);
+
+  useEffect(() => {
+    const reset = () => {
+      setIsIdle(false);
+      if (timerRef.current) clearTimeout(timerRef.current);
+      timerRef.current = setTimeout(() => setIsIdle(true), timeoutMs);
+    };
+
+    reset();
+    const events: Array<keyof WindowEventMap> = [
+      "mousemove",
+      "pointerdown",
+      "touchstart",
+      "keydown",
+    ];
+    events.forEach((event) => window.addEventListener(event, reset, { passive: true }));
+
+    return () => {
+      if (timerRef.current) clearTimeout(timerRef.current);
+      events.forEach((event) => window.removeEventListener(event, reset));
+    };
+  }, [timeoutMs]);
+
+  return isIdle;
+}