fix issues in core

core/notifications/infrastructure/index.ts

@@ -2,10 +2,5 @@
  * Infrastructure layer exports for notifications package
  */
 
-// Repositories
-export { InMemoryNotificationRepository } from './repositories/InMemoryNotificationRepository';
-export { InMemoryNotificationPreferenceRepository } from './repositories/InMemoryNotificationPreferenceRepository';
-
-// Adapters
-export { InAppNotificationAdapter } from "./InAppNotificationAdapter";
-export { NotificationGatewayRegistry } from "./NotificationGatewayRegistry";
+// This infrastructure layer is empty as the actual implementations
+// are in the adapters directory