feat: 增加滑动参与感 - 进度条、实时气泡、热度标签

- 卡片上方显示滑动进度条和计数 (3/15)
- 轮询检测到当前卡片新增 like 时弹出"有人也想去这家！"气泡
- 卡片图片角落显示"🔥N 人想去"热度标签
- 后端 GET /api/room/[id] 新增 likeCounts 字段

src/app/api/room/[id]/route.ts

@@ -37,12 +37,20 @@ export async function GET(
       matchLikes = best.likes;
     }
 
+    const likeCounts: Record<string, number> = {};
+    for (const [rid, users] of Object.entries(data.likes)) {
+      if (users.length > 0) {
+        likeCounts[rid] = users.length;
+      }
+    }
+
     return NextResponse.json({
       roomId: id,
       userCount: data.users.length,
       match,
       matchType,
       matchLikes,
+      likeCounts,
       restaurants: data.restaurants,
     });
   } catch (e) {