feat: 新增数据看板与用户管理模块

- 数据看板：注册用户 / 图章收集 / 兑换次数 三张卡片，展示总数及本日 / 本周 / 本月新增
- 时间边界按 Asia/Shanghai 计算，周一为一周起点
- 用户管理：只读列表展示用户名、手机号、已收集、已兑换及注册时间，支持搜索
- 登录后默认跳转到数据看板，侧边栏重新编号为 7 项

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

packages/server/src/routes/admin.ts

@@ -195,6 +195,71 @@ router.get("/stats", async (_req, res) => {
   res.json({ success: true, data: { userCount, collectionCount, redemptionCount } });
 });
 
+// Asia/Shanghai 边界（UTC+8，无夏令时）
+function shanghaiBoundaries() {
+  const OFFSET_MS = 8 * 60 * 60 * 1000;
+  const nowShanghai = new Date(Date.now() + OFFSET_MS);
+  const y = nowShanghai.getUTCFullYear();
+  const m = nowShanghai.getUTCMonth();
+  const d = nowShanghai.getUTCDate();
+  const weekdaySun0 = nowShanghai.getUTCDay();
+  const mondayOffset = (weekdaySun0 + 6) % 7;
+  const startOfToday = new Date(Date.UTC(y, m, d) - OFFSET_MS);
+  const startOfWeek = new Date(startOfToday.getTime() - mondayOffset * 86_400_000);
+  const startOfMonth = new Date(Date.UTC(y, m, 1) - OFFSET_MS);
+  return { startOfToday, startOfWeek, startOfMonth };
+}
+
+router.get("/dashboard", async (_req, res) => {
+  const { startOfToday, startOfWeek, startOfMonth } = shanghaiBoundaries();
+
+  const [
+    uTotal, uDay, uWeek, uMonth,
+    cTotal, cDay, cWeek, cMonth,
+    rTotal, rDay, rWeek, rMonth,
+  ] = await Promise.all([
+    prisma.user.count(),
+    prisma.user.count({ where: { createdAt: { gte: startOfToday } } }),
+    prisma.user.count({ where: { createdAt: { gte: startOfWeek } } }),
+    prisma.user.count({ where: { createdAt: { gte: startOfMonth } } }),
+    prisma.collection.count(),
+    prisma.collection.count({ where: { collectedAt: { gte: startOfToday } } }),
+    prisma.collection.count({ where: { collectedAt: { gte: startOfWeek } } }),
+    prisma.collection.count({ where: { collectedAt: { gte: startOfMonth } } }),
+    prisma.redemption.count(),
+    prisma.redemption.count({ where: { redeemedAt: { gte: startOfToday } } }),
+    prisma.redemption.count({ where: { redeemedAt: { gte: startOfWeek } } }),
+    prisma.redemption.count({ where: { redeemedAt: { gte: startOfMonth } } }),
+  ]);
+
+  res.json({
+    success: true,
+    data: {
+      users: { total: uTotal, today: uDay, thisWeek: uWeek, thisMonth: uMonth },
+      collections: { total: cTotal, today: cDay, thisWeek: cWeek, thisMonth: cMonth },
+      redemptions: { total: rTotal, today: rDay, thisWeek: rWeek, thisMonth: rMonth },
+    },
+  });
+});
+
+router.get("/users", async (_req, res) => {
+  const users = await prisma.user.findMany({
+    orderBy: { createdAt: "desc" },
+    include: {
+      _count: { select: { collections: true, redemptions: true } },
+    },
+  });
+  const data = users.map((u) => ({
+    id: u.id,
+    username: u.username,
+    phone: u.phone,
+    createdAt: u.createdAt,
+    collectionCount: u._count.collections,
+    redemptionCount: u._count.redemptions,
+  }));
+  res.json({ success: true, data });
+});
+
 // ===== Articles CRUD =====
 
 router.get("/articles", async (_req, res) => {