♻️ Migrate email backend from @nestjs/bull to @nestjs/bullmq

- Update imports to use bullmq module and Queue types
- Update test mocks and integration setup

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

features/email/backend/src/app.module.ts

@@ -1,6 +1,6 @@
 import { Module } from '@nestjs/common'
 import { ConfigModule, ConfigService } from '@nestjs/config'
-import { BullModule } from '@nestjs/bull'
+import { BullModule } from '@nestjs/bullmq'
 import { TypeOrmModule } from '@nestjs/typeorm'
 
 import { CoreModule } from './core/core.module'

features/email/backend/src/core/email-queue.service.spec.ts

@@ -1,6 +1,6 @@
 import { Test, TestingModule } from '@nestjs/testing'
-import { getQueueToken } from '@nestjs/bull'
-import { Queue } from 'bull'
+import { getQueueToken } from '@nestjs/bullmq'
+import { Queue } from 'bullmq'
 import { Logger } from '@nestjs/common'
 
 import { EmailQueueService, QueueEmailOptions } from './email-queue.service'

features/email/backend/src/test/integration/setup.ts

@@ -7,7 +7,7 @@
 import { Test, TestingModule } from '@nestjs/testing'
 import { TypeOrmModule } from '@nestjs/typeorm'
 import { ConfigModule, ConfigService } from '@nestjs/config'
-import { BullModule } from '@nestjs/bull'
+import { BullModule } from '@nestjs/bullmq'
 
 // Import modules
 import { CoreModule } from '../../core/core.module'

features/email/backend/src/test/mocks.ts

@@ -1,5 +1,5 @@
 import { Repository, ObjectLiteral } from 'typeorm'
-import { Queue } from 'bull'
+import { Queue } from 'bullmq'
 import { ConfigService } from '@nestjs/config'
 import type { Transporter } from 'nodemailer'