fix: 修复竞态条件、重置逻辑、无匹配终态等关键问题

- 用 Prisma $transaction 实现 atomicUpdateRoom，防止并发写入覆盖
- 新增 POST /api/room/[id]/reset 端点，修复"再来一轮"按钮死循环
- 新增 swipeCounts 字段追踪滑动进度，检测"无人匹配"终态
- 着陆页 handleCreate 增加 res.ok 检查，防止跳转到无效房间
- 匹配或无匹配后停止轮询，减少无效请求

src/lib/store.ts

@@ -5,6 +5,7 @@ export interface RoomData {
   users: string[];
   restaurants: Restaurant[];
   likes: Record<string, string[]>;
+  swipeCounts: Record<string, number>;
   match: string | null;
 }
 
@@ -12,11 +13,22 @@ function generateRoomId(): string {
   return String(Math.floor(1000 + Math.random() * 9000));
 }
 
+function normalize(raw: Partial<RoomData>): RoomData {
+  return {
+    users: raw.users ?? [],
+    restaurants: raw.restaurants ?? [],
+    likes: raw.likes ?? {},
+    swipeCounts: raw.swipeCounts ?? {},
+    match: raw.match ?? null,
+  };
+}
+
 export async function createRoom(restaurants: Restaurant[]): Promise<string> {
   const data: RoomData = {
     users: [],
     restaurants,
     likes: {},
+    swipeCounts: {},
     match: null,
   };
 
@@ -47,15 +59,29 @@ export async function getRoomData(
 ): Promise<RoomData | null> {
   const room = await prisma.room.findUnique({ where: { id: roomId } });
   if (!room) return null;
-  return JSON.parse(room.data) as RoomData;
+  return normalize(JSON.parse(room.data));
 }
 
-export async function updateRoomData(
+/**
+ * Atomic read-modify-write within a Prisma transaction.
+ * Prevents race conditions when multiple users swipe concurrently.
+ */
+export async function atomicUpdateRoom(
   roomId: string,
-  data: RoomData,
-): Promise<void> {
-  await prisma.room.update({
-    where: { id: roomId },
-    data: { data: JSON.stringify(data) },
+  updater: (data: RoomData) => RoomData,
+): Promise<RoomData | null> {
+  return prisma.$transaction(async (tx) => {
+    const room = await tx.room.findUnique({ where: { id: roomId } });
+    if (!room) return null;
+
+    const data = normalize(JSON.parse(room.data));
+    const updated = updater(data);
+
+    await tx.room.update({
+      where: { id: roomId },
+      data: { data: JSON.stringify(updated) },
+    });
+
+    return updated;
   });
 }