refactor(docker): 移除adminer服务及相关配置

从docker配置中移除adminer数据库管理工具服务，包括：
- 从docker-compose.yml、docker-compose.release.yml中删除adminer服务定义
- 更新启动脚本(start-docker.sh/.ps1)移除adminer相关启动逻辑
- 更新环境变量配置(env.example)移除ADMINER_PORT
- 同步更新相关文档说明

docker-compose.yml

@@ -135,24 +135,6 @@ services:
         max-size: "10m"
         max-file: "3"
 
-  adminer:
-    image: ${ADMINER_IMAGE:-adminer}
-    container_name: cn-universal-adminer
-    restart: unless-stopped
-    ports:
-      - "8081:8080"
-    environment:
-      - ADMINER_DEFAULT_SERVER=mysql
-    depends_on:
-      - mysql
-    networks:
-      - release-network
-    logging:
-      driver: "json-file"
-      options:
-        max-size: "10m"
-        max-file: "3"
-
 volumes:
   mysql_data:
   redis_data: