feat(notifications): R2.8 residential WS events (TEC-2759)

- Add emitResidentialEvent helper on NotificationsGateway that fans
  residential:price-drop, residential:new-listing-in-project, and
  residential:inquiry-reply to the user's /notifications room.
- Wire three CQRS @EventsHandler listeners on ListingPriceChangedEvent
  (only when newPrice < oldPrice, match saved searches),
  ListingApprovedEvent (match saved searches with filters.projectId
  against property.projectDevelopmentId), and InquiryReadEvent
  (notify inquiry author).
- Redis pub/sub fan-out already handled by RedisIoAdapter from
  TEC-2766, so these broadcasts work across API instances.
- Unit tests for all three listeners and the new gateway helper.

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

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

@@ -14,6 +14,11 @@ import { PaymentFailedListener } from './application/listeners/payment-failed.li
 import { PaymentRefundedListener } from './application/listeners/payment-refunded.listener';
 import { PhoneChangeRequestedListener } from './application/listeners/phone-change-requested.listener';
 import { QuotaExceededListener } from './application/listeners/quota-exceeded.listener';
+import {
+  ResidentialInquiryReplyListener,
+  ResidentialNewListingInProjectListener,
+  ResidentialPriceDropListener,
+} from './application/listeners/residential-events.listener';
 import { SubscriptionExpiredListener } from './application/listeners/subscription-expired.listener';
 import { SubscriptionExpiringListener } from './application/listeners/subscription-expiring.listener';
 import { SubscriptionRenewedListener } from './application/listeners/subscription-renewed.listener';
@@ -51,6 +56,9 @@ const EventListeners = [
   UserKycUpdatedListener,
   EmailChangeRequestedListener,
   PhoneChangeRequestedListener,
+  ResidentialPriceDropListener,
+  ResidentialNewListingInProjectListener,
+  ResidentialInquiryReplyListener,
 ];
 
 @Module({