feat(shared): add shared module with domain primitives, infrastructure services, and utils

Domain primitives: BaseEntity, AggregateRoot, ValueObject, DomainEvent, Result<T,E>
Infrastructure: PrismaService, RedisService, LoggerService (pino), EventBusService
Utils: Vietnam phone validator/normalizer, VND currency formatter, Vietnamese slug generator
Includes 45 unit tests covering all domain primitives, validators, and formatters.

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

apps/api/src/modules/shared/infrastructure/event-bus.service.ts

@@ -0,0 +1,22 @@
+import { Injectable } from '@nestjs/common';
+import { type EventEmitter2 } from '@nestjs/event-emitter';
+import { type DomainEvent } from '../domain/domain-event';
+
+@Injectable()
+export class EventBusService {
+  constructor(private readonly eventEmitter: EventEmitter2) {}
+
+  publish(event: DomainEvent): void {
+    this.eventEmitter.emit(event.eventName, event);
+  }
+
+  publishAll(events: DomainEvent[]): void {
+    for (const event of events) {
+      this.publish(event);
+    }
+  }
+
+  async publishAsync(event: DomainEvent): Promise<void> {
+    await this.eventEmitter.emitAsync(event.eventName, event);
+  }
+}