feat: add trip preference overrides with precedence resolution

backend/libs/trips/src/trips.module.ts

@@ -11,6 +11,8 @@ import { TripInvitationsRepository } from './trip-invitations.repository';
 import { TripInvitationsService } from './trip-invitations.service';
 import { TravelersRepository } from './travelers.repository';
 import { TravelersService } from './travelers.service';
+import { TripPreferenceOverridesRepository } from './trip-preference-overrides.repository';
+import { TripPreferenceOverridesService } from './trip-preference-overrides.service';
 
 @Module({
   imports: [DatabaseModule],
@@ -26,6 +28,8 @@ import { TravelersService } from './travelers.service';
     TripInvitationsService,
     TravelersRepository,
     TravelersService,
+    TripPreferenceOverridesRepository,
+    TripPreferenceOverridesService,
   ],
   exports: [
     TripsService,
@@ -34,6 +38,7 @@ import { TravelersService } from './travelers.service';
     TripMembershipGuard,
     TripInvitationsService,
     TravelersService,
+    TripPreferenceOverridesService,
   ],
 })
 export class TripsLibModule {}