feat: 拆分"再来一轮"为 Top N 决赛和换一批餐厅两个选项

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

@@ -2,13 +2,27 @@ import { NextResponse } from "next/server";
 import { atomicUpdateRoom } from "@/lib/store";
 
 export async function POST(
-  _req: Request,
+  req: Request,
   { params }: { params: Promise<{ id: string }> },
 ) {
   const { id } = await params;
 
+  let restaurantIds: string[] | undefined;
+  try {
+    const body = await req.json().catch(() => null);
+    if (body?.restaurantIds && Array.isArray(body.restaurantIds)) {
+      restaurantIds = body.restaurantIds;
+    }
+  } catch {
+    // No body or invalid JSON — plain reset
+  }
+
   try {
     const updated = await atomicUpdateRoom(id, (data) => {
+      if (restaurantIds && restaurantIds.length > 0) {
+        const idSet = new Set(restaurantIds);
+        data.restaurants = data.restaurants.filter((r) => idSet.has(r.id));
+      }
       data.likes = {};
       data.swipeCounts = {};
       data.match = null;

src/app/room/[id]/page.tsx

@@ -34,6 +34,15 @@ export default function RoomPage() {
     await mutate();
   }, [roomId, mutate]);
 
+  const handleNarrow = useCallback(async (restaurantIds: string[]) => {
+    await fetch(`/api/room/${roomId}/reset`, {
+      method: "POST",
+      headers: { "Content-Type": "application/json" },
+      body: JSON.stringify({ restaurantIds }),
+    });
+    await mutate();
+  }, [roomId, mutate]);
+
   const initialIndex = swipeCounts[userId] ?? 0;
   const ready = joined && userId && restaurants.length > 0;
 
@@ -62,6 +71,7 @@ export default function RoomPage() {
         swipeCounts={swipeCounts}
         userCount={userCount}
         onReset={handleReset}
+        onNarrow={handleNarrow}
       />
     </div>
   );