fix(admin-service): 在主 docker-compose.yml 中添加 Kafka 配置

在 backend/services/docker-compose.yml 中为 admin-service 添加:
- KAFKA_BROKERS=kafka:29092
- KAFKA_CLIENT_ID=admin-service
- KAFKA_CONSUMER_GROUP=admin-service-user-sync
- kafka 服务依赖

确保生产环境部署时能正确连接 Kafka 同步用户数据。

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

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

backend/services/docker-compose.yml

@@ -523,11 +523,16 @@ services:
       - REDIS_PORT=6379
       - REDIS_PASSWORD=${REDIS_PASSWORD:-}
       - REDIS_DB=9
+      - KAFKA_BROKERS=kafka:29092
+      - KAFKA_CLIENT_ID=admin-service
+      - KAFKA_CONSUMER_GROUP=admin-service-user-sync
     depends_on:
       postgres:
         condition: service_healthy
       redis:
         condition: service_healthy
+      kafka:
+        condition: service_started
     healthcheck:
       test: ["CMD", "curl", "-f", "http://localhost:3010/api/v1/health"]
       interval: 30s