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

server/src/config.js

@@ -32,4 +32,9 @@ const config = {
   }
 }
 
+if (config.nodeEnv === 'production') {
+  if (config.jwt.secret === 'dev-user-secret') throw new Error('JWT_SECRET must be set in production')
+  if (config.jwt.adminSecret === 'dev-admin-secret') throw new Error('ADMIN_JWT_SECRET must be set in production')
+}
+
 module.exports = config