feat(notifications): R8.1 Stringee SMS adapter + rate limiting (TEC-2764)

- Add NotificationChannelPort domain port for SMS/transactional channels.
- Refactor StringeeSmsService to implement the port; routes OTP template
  keys through the tighter otp bucket and transactional keys through the
  wider bucket.
- Add SmsRateLimiterService using a Redis sorted-set sliding window with
  per-minute + per-hour limits per phone; fails open on Redis errors.
- Rate-limit violations throw DomainException(TOO_MANY_REQUESTS, 429)
  with retryAfterSeconds in the details payload.
- Cover adapter + rate limiter with unit tests (22 specs); all 148
  notifications tests still green.

Co-Authored-By: Paperclip <noreply@paperclip.ing>

apps/api/src/modules/notifications/notifications.module.ts

@@ -24,12 +24,14 @@ import { SubscriptionExpiringListener } from './application/listeners/subscripti
 import { SubscriptionRenewedListener } from './application/listeners/subscription-renewed.listener';
 import { UserKycUpdatedListener } from './application/listeners/user-kyc-updated.listener';
 import { UserRegisteredListener } from './application/listeners/user-registered.listener';
+import { SMS_NOTIFICATION_CHANNEL } from './domain/ports/notification-channel.port';
 import { NOTIFICATION_PREFERENCE_REPOSITORY } from './domain/repositories/notification-preference.repository';
 import { NOTIFICATION_REPOSITORY } from './domain/repositories/notification.repository';
 import { PrismaNotificationPreferenceRepository } from './infrastructure/repositories/prisma-notification-preference.repository';
 import { PrismaNotificationRepository } from './infrastructure/repositories/prisma-notification.repository';
 import { EmailService } from './infrastructure/services/email.service';
 import { FcmService } from './infrastructure/services/fcm.service';
+import { SmsRateLimiterService } from './infrastructure/services/sms-rate-limiter.service';
 import { StringeeSmsService } from './infrastructure/services/stringee-sms.service';
 import { TemplateService } from './infrastructure/services/template.service';
 import { ZaloOaService } from './infrastructure/services/zalo-oa.service';
@@ -72,7 +74,9 @@ const EventListeners = [
     // Services
     EmailService,
     FcmService,
+    SmsRateLimiterService,
     StringeeSmsService,
+    { provide: SMS_NOTIFICATION_CHANNEL, useExisting: StringeeSmsService },
     ZaloOaService,
     TemplateService,
 
@@ -85,6 +89,15 @@ const EventListeners = [
     // Event Listeners
     ...EventListeners,
   ],
-  exports: [EmailService, FcmService, StringeeSmsService, ZaloOaService, TemplateService, NotificationsGateway],
+  exports: [
+    EmailService,
+    FcmService,
+    SmsRateLimiterService,
+    StringeeSmsService,
+    SMS_NOTIFICATION_CHANNEL,
+    ZaloOaService,
+    TemplateService,
+    NotificationsGateway,
+  ],
 })
 export class NotificationsModule {}