feat: 两级匹配机制 - 全票通过即时匹配 + 滑完自动推荐得票最高

- 后端 GET /api/room/[id] 新增 findBestMatch，滑完后选出得票最高餐厅
- 平票时取高德评分更高的一家，永远不会出现"无结果"死局
- 返回 matchType (unanimous/best) 和 matchLikes 区分匹配类型
- 全票通过：绿色庆祝 + "大家一拍即合！"
- 得票最高：橙色推荐 + "N/M 人想去这家"
- 移除 noMatch 死局页面，简化 SwipeDeck 状态管理

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

@@ -1,5 +1,6 @@
 import { NextResponse } from "next/server";
 import { getRoomData } from "@/lib/store";
+import type { MatchType } from "@/types";
 
 export async function GET(
   _req: Request,
@@ -21,13 +22,29 @@ export async function GET(
     const allFinished =
       data.users.length > 0 &&
       data.users.every((u) => (data.swipeCounts[u] ?? 0) >= total);
-    const noMatch = allFinished && data.match === null;
+
+    let match = data.match;
+    let matchType: MatchType = null;
+    let matchLikes = 0;
+
+    if (match) {
+      matchType = "unanimous";
+      matchLikes = data.users.length;
+    } else if (allFinished) {
+      const best = findBestMatch(data.likes, data.restaurants);
+      if (best) {
+        match = best.id;
+        matchType = "best";
+        matchLikes = best.likes;
+      }
+    }
 
     return NextResponse.json({
       roomId: id,
       userCount: data.users.length,
-      match: data.match,
-      noMatch,
+      match,
+      matchType,
+      matchLikes,
       restaurants: data.restaurants,
     });
   } catch (e) {
@@ -38,3 +55,29 @@ export async function GET(
     );
   }
 }
+
+function findBestMatch(
+  likes: Record<string, string[]>,
+  restaurants: { id: string; rating: number }[],
+): { id: string; likes: number } | null {
+  let bestId: string | null = null;
+  let bestLikes = 0;
+  let bestRating = 0;
+
+  for (const r of restaurants) {
+    const count = likes[r.id]?.length ?? 0;
+    if (count === 0) continue;
+
+    if (
+      count > bestLikes ||
+      (count === bestLikes && r.rating > bestRating)
+    ) {
+      bestId = r.id;
+      bestLikes = count;
+      bestRating = r.rating;
+    }
+  }
+
+  if (!bestId) return null;
+  return { id: bestId, likes: bestLikes };
+}