fix: comprehensive security, quality and consistency fixes

Server:
- Block startup with default JWT secrets in production
- Make subscription verify admin-only (no payment integration yet)
- Add device ownership validation on command/result, event, treatment/sync
- Remove admin token from request body fallback
- Add pageParams boundary protection (pageSize capped at 100)
- Fix COS getObjectUrl to use callback-based Promise
- Add settings key whitelist matching frontend fields
- Add user existence check before subscription creation
- Fix firmware always returning has_update:true
- Replace hardcoded trial subscription with actual DB query
- Extract shared utilities (limitClause, toMysqlDate, formatDate)

Miniprogram:
- Replace fake PD random data with placeholder
- Mark client-timer treatment completions with source field
- Disable mock.js
- Fix BLE listener leaks (save refs, cleanup in onUnload)
- Fix ble.off clearing all listeners (pass specific callback)
- Add BLE disconnect detection via onBLEConnectionStateChange
- Fix subscription status type consistency (number not string)
- Fix scan callback accumulation in ble.js
- Fix history stats accumulation across pages
- Fix subscribe-success/treatment-done hardcoded values
- Fix profile subscription view logic
- Replace purchase flow with admin-contact modal
- Add error logging in command-sync report

Admin console:
- Fix AdminLayout logout (require->import, logout->clearToken)
- Remove all mock data from production request.js
- Replace dashboard fake data with real API calls
- Replace monthly_revenue with subscription_count
- Fix subscription stats fallback (|| -> ??)
- Add token expiry tracking (7 days)
- Unify device status map and subscription status text
- Fix user page record link navigation
- Fix subscription createForm.user_id type handling
- Add error feedback in all empty catch blocks
- Remove unused remember checkbox and uview-plus dependency
- Extract common CSS to shared stylesheet (-900 lines)
- Extract formatDate to shared utils/format.js
- Show real admin name in layout header

miniprogram/pages/subscribe-plans/subscribe-plans.js

@@ -21,27 +21,10 @@ Page({
   },
 
   onPurchase: function () {
-    var self = this
-    if (!self.data.selected) {
-      wx.showToast({ title: '请选择套餐', icon: 'none' })
-      return
-    }
-    self.setData({ purchasing: true })
-
-    http.post('/api/v1/subscription/purchase', {
-      plan_type: self.data.selected,
-      payment_method: 'wechat'
-    }).then(function (data) {
-      return http.post('/api/v1/subscription/verify', {
-        order_id: data.order_id,
-        plan_type: self.data.selected
-      })
-    }).then(function () {
-      self.setData({ purchasing: false })
-      wx.redirectTo({ url: '/pages/subscribe-success/subscribe-success' })
-    }).catch(function () {
-      self.setData({ purchasing: false })
-      wx.showToast({ title: '购买失败', icon: 'none' })
+    wx.showModal({
+      title: '暂未开放',
+      content: '在线购买功能尚未开放，请联系管理员开通订阅。',
+      showCancel: false
     })
   }
 })