fix: resolve quality audit issues

- utils.js: force UTC+8 output to match MySQL timezone on SCF
- admin subscriptions: return stats (plan counts + revenue) in response
- admin devices: implement keyword search filter
- device-detail: fix binding history field names (bind_time/unbind_time/bind_status)
- user-detail: fix treatment time field (start_time not started_at)
- dashboard: show actual mode per treatment, use sub_stats from dashboard API

server/src/routes/admin.js

@@ -78,8 +78,15 @@ function register(router) {
     const admin = await requireAdmin(ctx)
     if (!admin) return fail(1002, '未授权，请重新登录')
     const p = pageParams(ctx)
-    const total = await query('SELECT COUNT(*) AS total FROM devices', {})
-    const records = await query('SELECT d.*, b.user_id AS bound_user, b.bind_time AS activated_at FROM devices d LEFT JOIN bindings b ON b.device_id = d.device_id AND b.bind_status = 1 ORDER BY d.created_at DESC' + limitClause(p.pageSize, p.offset), {})
+    const keyword = (ctx.query.keyword || '').trim()
+    let where = ''
+    const params = {}
+    if (keyword) {
+      where = ' WHERE d.device_id LIKE :kw OR d.device_name LIKE :kw'
+      params.kw = '%' + keyword + '%'
+    }
+    const total = await query('SELECT COUNT(*) AS total FROM devices d' + where, params)
+    const records = await query('SELECT d.*, b.user_id AS bound_user, b.bind_time AS activated_at FROM devices d LEFT JOIN bindings b ON b.device_id = d.device_id AND b.bind_status = 1' + where + ' ORDER BY d.created_at DESC' + limitClause(p.pageSize, p.offset), params)
     return ok({ records, total: total[0].total })
   })
 
@@ -239,7 +246,13 @@ function register(router) {
       'SELECT s.*, u.nickname FROM subscriptions s LEFT JOIN users u ON u.user_id = s.user_id' + where + ' ORDER BY s.created_at DESC' + limitClause(p.pageSize, p.offset),
       params
     )
-    return ok({ records, total: total[0].total })
+    const statsRow = await query('SELECT ' +
+      'SUM(CASE WHEN plan = \'monthly\' AND status = 1 AND expire_time > NOW() THEN 1 ELSE 0 END) AS monthly_count, ' +
+      'SUM(CASE WHEN plan = \'yearly\' AND status = 1 AND expire_time > NOW() THEN 1 ELSE 0 END) AS yearly_count, ' +
+      'SUM(CASE WHEN plan = \'trial\' AND status = 1 AND expire_time > NOW() THEN 1 ELSE 0 END) AS trial_count, ' +
+      'COALESCE(SUM(CASE WHEN MONTH(start_time) = MONTH(NOW()) AND YEAR(start_time) = YEAR(NOW()) THEN amount ELSE 0 END), 0) AS monthly_revenue ' +
+      'FROM subscriptions', {})
+    return ok({ records, total: total[0].total, stats: statsRow[0] || {} })
   })
 
   router.post('/api/v1/admin/subscriptions', async ctx => {