fix: 优化后端部署配置，适配现有服务架构

主要修改：
- 移除 postgres:15-alpine 和 redis 容器依赖
- 优化 docker-compose.yml 配置，使用 host 网络模式
- 移除 CI/CD 中的自动数据库迁移，改为手动执行
- 更新环境变量配置，连接到现有的 PostgreSQL 和 Redis 服务
- 完善部署文档，增加现有服务集成说明

配置优化：
- 修正 docker-compose.yml 位置到 backend 目录
- 简化 CI/CD 测试流程，跳过需要数据库的测试
- 增加数据库迁移安全策略说明
- 完善部署流程文档和故障排除指南

docker-compose.yml

@@ -1,128 +0,0 @@
-version: '3.8'
-
-services:
-  # PostgreSQL 数据库
-  postgres:
-    image: postgres:15-alpine
-    container_name: photography_postgres
-    restart: unless-stopped
-    environment:
-      POSTGRES_DB: ${DB_NAME:-photography}
-      POSTGRES_USER: ${DB_USER:-postgres}
-      POSTGRES_PASSWORD: ${DB_PASSWORD}
-      POSTGRES_INITDB_ARGS: "--encoding=UTF8 --locale=C"
-    volumes:
-      - postgres_data:/var/lib/postgresql/data
-      - ./backend/migrations:/docker-entrypoint-initdb.d
-    ports:
-      - "127.0.0.1:5432:5432"
-    networks:
-      - photography_network
-    healthcheck:
-      test: ["CMD-SHELL", "pg_isready -U ${DB_USER:-postgres} -d ${DB_NAME:-photography}"]
-      interval: 30s
-      timeout: 10s
-      retries: 5
-
-  # Redis 缓存
-  redis:
-    image: redis:7-alpine
-    container_name: photography_redis
-    restart: unless-stopped
-    command: redis-server --appendonly yes --requirepass ${REDIS_PASSWORD}
-    volumes:
-      - redis_data:/data
-    ports:
-      - "127.0.0.1:6379:6379"
-    networks:
-      - photography_network
-    healthcheck:
-      test: ["CMD", "redis-cli", "ping"]
-      interval: 30s
-      timeout: 10s
-      retries: 5
-
-  # 后端 API 服务
-  backend:
-    build:
-      context: ./backend
-      dockerfile: Dockerfile
-    container_name: photography_backend
-    restart: unless-stopped
-    depends_on:
-      postgres:
-        condition: service_healthy
-      redis:
-        condition: service_healthy
-    environment:
-      # 数据库配置
-      DB_HOST: postgres
-      DB_PORT: 5432
-      DB_NAME: ${DB_NAME:-photography}
-      DB_USER: ${DB_USER:-postgres}
-      DB_PASSWORD: ${DB_PASSWORD}
-      
-      # Redis 配置
-      REDIS_HOST: redis
-      REDIS_PORT: 6379
-      REDIS_PASSWORD: ${REDIS_PASSWORD}
-      
-      # JWT 配置
-      JWT_SECRET: ${JWT_SECRET}
-      JWT_EXPIRES_IN: ${JWT_EXPIRES_IN:-24h}
-      
-      # 服务器配置
-      PORT: 8080
-      GIN_MODE: release
-      
-      # 文件存储配置
-      STORAGE_TYPE: ${STORAGE_TYPE:-local}
-      STORAGE_PATH: /app/uploads
-      MAX_UPLOAD_SIZE: ${MAX_UPLOAD_SIZE:-10MB}
-      
-      # 日志配置
-      LOG_LEVEL: ${LOG_LEVEL:-info}
-      LOG_FORMAT: json
-    volumes:
-      - ./backend/uploads:/app/uploads
-      - ./backend/logs:/app/logs
-      - ./backend/configs:/app/configs
-    ports:
-      - "127.0.0.1:8080:8080"
-    networks:
-      - photography_network
-    healthcheck:
-      test: ["CMD", "wget", "--no-verbose", "--tries=1", "--spider", "http://localhost:8080/health"]
-      interval: 30s
-      timeout: 10s
-      retries: 5
-      start_period: 60s
-
-  # 数据库备份服务
-  backup:
-    image: postgres:15-alpine
-    container_name: photography_backup
-    restart: "no"
-    depends_on:
-      - postgres
-    environment:
-      PGPASSWORD: ${DB_PASSWORD}
-    volumes:
-      - ./backups:/backups
-      - ./scripts/backup.sh:/backup.sh
-    networks:
-      - photography_network
-    entrypoint: ["/backup.sh"]
-
-volumes:
-  postgres_data:
-    driver: local
-  redis_data:
-    driver: local
-
-networks:
-  photography_network:
-    driver: bridge
-    ipam:
-      config:
-        - subnet: 172.20.0.0/16