fix: 客户端资源清理 — ShareCard 依赖 + 定时器 + 死代码

- #20: ShareCardModal useEffect 依赖改为 imageSrc 字符串，避免对象引用变化重复加载
- #21: BlindboxRoomPage 所有 setTimeout/rAF 统一收集，unmount 时清理
- #25: 删除未使用的 confettiCanvasRef 和 canvas 元素

src/app/blindbox/[code]/page.tsx

@@ -65,7 +65,15 @@ export default function BlindboxRoomPage() {
 
   const boxControls = useAnimation();
   const inputRef = useRef<HTMLInputElement>(null);
-  const confettiCanvasRef = useRef<HTMLCanvasElement>(null);
+  const timersRef = useRef<ReturnType<typeof setTimeout>[]>([]);
+  const confettiAliveRef = useRef(false);
+
+  useEffect(() => {
+    return () => {
+      timersRef.current.forEach(clearTimeout);
+      confettiAliveRef.current = false;
+    };
+  }, []);
 
   useEffect(() => {
     if (!isRegistered()) {
@@ -121,7 +129,8 @@ export default function BlindboxRoomPage() {
 
   useEffect(() => {
     if (isMember && inputRef.current) {
-      setTimeout(() => inputRef.current?.focus(), 300);
+      const t = setTimeout(() => inputRef.current?.focus(), 300);
+      timersRef.current.push(t);
     }
   }, [isMember]);
 
@@ -162,7 +171,7 @@ export default function BlindboxRoomPage() {
       setPoolCount((c) => c + 1);
       setMyIdeas((prev) => [{ id, content: text, createdAt: new Date().toISOString() }, ...prev]);
       setSubmitFlash(true);
-      setTimeout(() => setSubmitFlash(false), 600);
+      timersRef.current.push(setTimeout(() => setSubmitFlash(false), 600));
       boxControls.start({
         scale: [1, 1.08, 1],
         rotate: [0, -3, 3, 0],
@@ -256,14 +265,15 @@ export default function BlindboxRoomPage() {
   const fireConfetti = () => {
     const colors = ["#a855f7", "#6366f1", "#ec4899", "#f59e0b", "#10b981"];
     confetti({ particleCount: 100, spread: 120, origin: { y: 0.4 }, colors, startVelocity: 45, ticks: 250 });
+    confettiAliveRef.current = true;
     const end = Date.now() + 3000;
     const frame = () => {
-      if (Date.now() > end) return;
+      if (Date.now() > end || !confettiAliveRef.current) return;
       confetti({ particleCount: 3, angle: 60, spread: 55, origin: { x: 0, y: 0.6 }, colors, startVelocity: 35, ticks: 150 });
       confetti({ particleCount: 3, angle: 120, spread: 55, origin: { x: 1, y: 0.6 }, colors, startVelocity: 35, ticks: 150 });
       requestAnimationFrame(frame);
     };
-    setTimeout(frame, 200);
+    timersRef.current.push(setTimeout(frame, 200));
   };
 
   const { share, copyToClipboard } = useShare();
@@ -287,7 +297,7 @@ export default function BlindboxRoomPage() {
   const handleLeaveOrDelete = async () => {
     if (!confirmLeave) {
       setConfirmLeave(true);
-      setTimeout(() => setConfirmLeave(false), 3000);
+      timersRef.current.push(setTimeout(() => setConfirmLeave(false), 3000));
       return;
     }
     if (leaving || !profile || !room) return;
@@ -319,7 +329,6 @@ export default function BlindboxRoomPage() {
 
   return (
     <div className="relative flex min-h-dvh flex-col items-center bg-background px-5 py-6 overflow-y-auto scrollbar-none">
-      <canvas ref={confettiCanvasRef} className="pointer-events-none fixed inset-0 z-50" />
 
       {/* Header */}
       <div className="flex w-full max-w-sm items-center gap-3">

src/components/ShareCardModal.tsx

@@ -38,21 +38,20 @@ export default function ShareCardModal({
   const [imageDataUrl, setImageDataUrl] = useState<string | null>(null);
   const [imageLoading, setImageLoading] = useState(false);
 
+  const imageSrc = data.type === "restaurant" ? data.restaurant.images?.[0] : undefined;
+
   useEffect(() => {
     if (!open) {
       setImageDataUrl(null);
       return;
     }
-    if (data.type !== "restaurant") return;
+    if (!imageSrc) return;
-
-    const src = data.restaurant.images?.[0];
-    if (!src) return;
 
     setImageLoading(true);
-    loadImageAsDataUrl(src)
+    loadImageAsDataUrl(imageSrc)
       .then(setImageDataUrl)
       .finally(() => setImageLoading(false));
-  }, [open, data]);
+  }, [open, imageSrc]);
 
   const handleGenerate = useCallback(async (): Promise<string | null> => {
     if (!cardRef.current) return null;