feat(notifications): add multi-channel notification module with Email, FCM, templates, and event listeners

- Domain: NotificationLog/NotificationPreference entities, repositories, channel value object
- Infrastructure: EmailService (nodemailer/SMTP), FcmService (firebase-admin), TemplateService (Handlebars)
- Application: SendNotification CQRS command, UserRegistered + AgentVerified event listeners
- Presentation: NotificationsController with history, preferences, and templates endpoints
- Prisma: NotificationLog and NotificationPreference models with proper indexes
- Templates: Vietnamese notification templates for user.registered, agent.verified, listing.approved, inquiry.received, password.reset

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

apps/api/src/modules/notifications/infrastructure/services/email.service.ts

@@ -0,0 +1,63 @@
+import { Injectable, type OnModuleInit } from '@nestjs/common';
+import { LoggerService } from '@modules/shared/infrastructure/logger.service';
+import * as nodemailer from 'nodemailer';
+
+export interface SendEmailDto {
+  to: string;
+  subject: string;
+  html: string;
+}
+
+@Injectable()
+export class EmailService implements OnModuleInit {
+  private transporter!: nodemailer.Transporter;
+
+  constructor(private readonly logger: LoggerService) {}
+
+  onModuleInit(): void {
+    const host = process.env['SMTP_HOST'] ?? 'localhost';
+    const port = Number(process.env['SMTP_PORT'] ?? '1025');
+    const user = process.env['SMTP_USER'];
+    const pass = process.env['SMTP_PASS'];
+
+    this.transporter = nodemailer.createTransport({
+      host,
+      port,
+      secure: port === 465,
+      ...(user && pass ? { auth: { user, pass } } : {}),
+    });
+
+    this.logger.log(`Email transport configured: ${host}:${port}`, 'EmailService');
+  }
+
+  async send(dto: SendEmailDto): Promise<{ messageId: string }> {
+    const from = process.env['SMTP_FROM'] ?? 'noreply@goodgo.vn';
+
+    try {
+      const info = await this.transporter.sendMail({
+        from,
+        to: dto.to,
+        subject: dto.subject,
+        html: dto.html,
+      });
+
+      this.logger.log(`Email sent to ${dto.to}: ${info.messageId}`, 'EmailService');
+      return { messageId: info.messageId };
+    } catch (error) {
+      this.logger.error(
+        `Failed to send email to ${dto.to}: ${error instanceof Error ? error.message : String(error)}`,
+        'EmailService',
+      );
+      throw error;
+    }
+  }
+
+  async verify(): Promise<boolean> {
+    try {
+      await this.transporter.verify();
+      return true;
+    } catch {
+      return false;
+    }
+  }
+}