fix(2.0-services): 修复InfrastructureModule导出PrismaService问题

NestJS不允许模块导出未在providers中声明的服务。
将exports中的PrismaService改为PrismaModule（因为PrismaModule已导出PrismaService）。

修复服务:
- mining-admin-service
- auth-service

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

backend/services/auth-service/src/infrastructure/infrastructure.module.ts

@@ -1,7 +1,6 @@
 import { Module, Global } from '@nestjs/common';
 import { ConfigModule, ConfigService } from '@nestjs/config';
 import { PrismaModule } from './persistence/prisma/prisma.module';
-import { PrismaService } from './persistence/prisma/prisma.service';
 import {
   PrismaUserRepository,
   PrismaSyncedLegacyUserRepository,
@@ -60,7 +59,7 @@ import {
     },
   ],
   exports: [
-    PrismaService,
+    PrismaModule,
     KafkaProducerService,
     RedisService,
     USER_REPOSITORY,

backend/services/mining-admin-service/src/infrastructure/infrastructure.module.ts

@@ -1,7 +1,6 @@
 import { Module, Global } from '@nestjs/common';
 import { ConfigModule, ConfigService } from '@nestjs/config';
 import { PrismaModule } from './persistence/prisma/prisma.module';
-import { PrismaService } from './persistence/prisma/prisma.service';
 import { RedisService } from './redis/redis.service';
 import { KafkaModule } from './kafka/kafka.module';
 
@@ -21,6 +20,6 @@ import { KafkaModule } from './kafka/kafka.module';
     },
     RedisService,
   ],
-  exports: [PrismaService, RedisService, KafkaModule],
+  exports: [PrismaModule, RedisService, KafkaModule],
 })
 export class InfrastructureModule {}