chore: remove all mock/debug code for production release

Miniprogram:
- ENV switched to 'prod' (disables __DEV__ flag)
- Deleted mock.js and test-ble-frame.js
- Removed mockBind/mockPurchase from api.js
- Removed all debug UI panels and onMock* handlers from 6 pages
- Removed mock purchase fallback in subscribe-plans
- Removed SIMPLE PERIPHERAL dev board from BLE scan

Server:
- Removed /device/mock-bind route
- Removed /subscription/mock-purchase route
- Removed dev_openid fallback in wechat.js
- Removed mockBind() from binding.dao.js
- Removed mock fallback in purchase endpoint
- NODE_ENV default changed to 'production'

Admin:
- ENV switched to 'prod'

All mock code preserved in 'test' branch for future development use.

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

@@ -1,5 +1,4 @@
 var api = require('../../utils/api')
-var config = require('../../config/env')
 
 Page({
   data: {
@@ -163,17 +162,12 @@ Page({
     var self = this
     self.setData({ purchasing: true })
     api.purchase(plan.key).then(function (data) {
-      if (data.mock || !data.payment_params) {
-        // Dev fallback: use mock purchase
-        return api.mockPurchase(plan.key).then(function () {
-          self.setData({ purchasing: false })
-          wx.showToast({ title: '支付成功', icon: 'success' })
-          setTimeout(function () {
-            wx.redirectTo({ url: '/pages/subscribe-success/subscribe-success?plan=' + plan.key })
-          }, 1000)
-        })
+      if (!data.payment_params) {
+        self.setData({ purchasing: false })
+        wx.showToast({ title: '支付服务暂不可用', icon: 'none' })
+        return
       }
-      // Real payment
+
       var params = data.payment_params
       self._currentOrderId = data.order_id
       wx.requestPayment({