chore: migrate backend to monorepo apps and biome

apps/notifications/src/notifications.module.ts

@@ -0,0 +1,10 @@
+import { Module } from '@nestjs/common';
+import { NotificationsController } from './notifications.controller';
+import { NotificationsService } from './notifications.service';
+
+@Module({
+  imports: [],
+  controllers: [NotificationsController],
+  providers: [NotificationsService],
+})
+export class NotificationsModule {}