fix: address critical security and data integrity issues from cross-audit

- Add expire_time > NOW() filter to findActive() preventing stale subscriptions
- Add express-rate-limit on login endpoints (user: 10/15min, admin: 5/15min)
- Add production guard for default admin credentials
- Fix BLE bindDevice userId encoding (uint32 instead of hexToBytes on numeric)
- Wrap adminCreate in transaction to prevent race condition
- Add settings cache invalidation after admin saves
- Read trial_days from settings instead of hardcoding 7
- Fix double JSON.stringify in commandDao.finish call
- Cancel stale pending bindings before creating new ones
- Reduce token refresh grace period from 3 days to 1 day
- Fix subscribe-success to fetch expiry from server (correct for renewals)
- Add keep-alive name property to DashboardView and SettingsView
- Fix BLE disconnect() to preserve listener registrations across reconnects

server/src/config.js

@@ -35,6 +35,7 @@ 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')
+  if (config.admin.username === 'admin' || config.admin.password === 'admin') throw new Error('ADMIN_USERNAME and ADMIN_PASSWORD must be changed from defaults in production')
 }
 
 module.exports = config