feat: 契约生命周期 + 到期通知 + 成就墙

- 扩展 WeekendPlan schema: 新增 endTime 字段与 userId 索引
- PATCH /api/blindbox/plan 支持 accept/complete/expire 操作，
  接受时自动计算契约结束时间
- GET /api/blindbox/plan 支持 mode 参数 (latest/pending/history)
- 房间页接受契约后自动返回想法池，顶部显示"契约进行中"指示器
- 契约到期时触发浏览器通知 + 页面加载时弹出完成确认弹窗
- 新增 /achievements 成就墙页面：统计数据 + 决策记录/契约记录双标签
- 首页和个人中心新增成就墙入口

src/app/api/user/achievements/route.ts

@@ -0,0 +1,77 @@
+import { NextResponse } from "next/server";
+import { prisma } from "@/lib/prisma";
+import { apiHandler, requireUserId } from "@/lib/api";
+
+export const GET = apiHandler(async (req) => {
+  const userId = req.nextUrl.searchParams.get("userId");
+  requireUserId(userId);
+
+  const [decisions, contracts] = await Promise.all([
+    prisma.decision.findMany({
+      where: { userId: userId! },
+      orderBy: { createdAt: "desc" },
+      take: 50,
+    }),
+    prisma.weekendPlan.findMany({
+      where: {
+        userId: userId!,
+        status: { in: ["completed", "expired"] },
+      },
+      orderBy: { createdAt: "desc" },
+      take: 50,
+      select: {
+        id: true,
+        planData: true,
+        status: true,
+        roomId: true,
+        createdAt: true,
+      },
+    }),
+  ]);
+
+  const roomIds = [...new Set(contracts.map((c) => c.roomId))];
+  const rooms = await prisma.blindBoxRoom.findMany({
+    where: { id: { in: roomIds } },
+    select: { id: true, name: true, code: true },
+  });
+  const roomMap = new Map(rooms.map((r) => [r.id, r]));
+
+  const completedCount = contracts.filter((c) => c.status === "completed").length;
+
+  const contractRecords = contracts.map((c) => {
+    const parsed = JSON.parse(c.planData);
+    const days = parsed.days as { date: string; items: { activity: string }[] }[];
+    const room = roomMap.get(c.roomId);
+    return {
+      id: c.id,
+      status: c.status,
+      roomName: room?.name ?? "未知房间",
+      roomCode: room?.code ?? "",
+      date: days.map((d) => d.date).join(" + "),
+      dayCount: days.length,
+      activities: days.flatMap((d) => d.items.map((i) => i.activity)),
+      createdAt: c.createdAt.toISOString(),
+    };
+  });
+
+  const decisionRecords = decisions.map((d) => ({
+    id: d.id,
+    roomId: d.roomId,
+    restaurantName: d.restaurantName,
+    restaurantData: JSON.parse(d.restaurantData),
+    matchType: d.matchType,
+    participants: d.participants,
+    createdAt: d.createdAt.toISOString(),
+  }));
+
+  return NextResponse.json({
+    stats: {
+      totalDecisions: decisions.length,
+      totalContracts: contracts.length,
+      completedContracts: completedCount,
+      completionRate: contracts.length > 0 ? Math.round((completedCount / contracts.length) * 100) : 0,
+    },
+    decisions: decisionRecords,
+    contracts: contractRecords,
+  });
+});