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/config/env.js

@@ -1,5 +1,5 @@
 // Production: change to 'prod' to disable debug buttons and mock endpoints
-var ENV = 'test'
+var ENV = 'prod'
 
 var API_BASES = {
   local: 'http://localhost:3000',