feat(phase1): 完成全局完善和基础设施文档

Task 6.1: 统一异常处理
- 创建 GlobalExceptionHandler：Spring 全局异常拦截器
  - SessionNotFoundException: 404 会话未找到
  - DocumentProcessException: 400 文档处理异常
  - MaxUploadSizeExceededException: 400 文件大小超限
  - IllegalArgumentException: 400 参数错误
  - Exception: 500 系统异常兜底
- 统一响应格式：Result<T> + HTTP 状态码

Task 6.2: Docker Compose 配置
- 创建 docker-compose.yml：本地开发环境一键启动
  - MySQL 8.0: 数据持久化，端口 3306
  - Redis 7: 会话缓存，端口 6379
  - Milvus Standalone: 向量索引，端口 19530
    - etcd: 元数据存储
    - MinIO: 对象存储
- 数据卷持久化：mysql-data, redis-data, milvus-data
- 健康检查：自动重启机制

Task 6.3: 更新 README.md
- 新增 Phase 1 专属章节：
  - 架构概览（已完成功能清单）
  - 本地开发环境（前置要求、快速开始）
  - 数据库迁移（Flyway 脚本说明）
  - API 文档（文档管理接口示例）
  - 项目结构（分层架构说明）
  - 待办事项（向量化索引、混合检索）
  - 技术决策（包名重构、文本格式、分块策略）

编译验证：BUILD SUCCESS

Progress: 31/33 tasks completed (94%)

docker-compose.yml

@@ -0,0 +1,108 @@
+version: '3.8'
+
+services:
+  # MySQL 数据库
+  mysql:
+    image: mysql:8.0
+    container_name: superbiz-mysql
+    restart: always
+    environment:
+      MYSQL_ROOT_PASSWORD: root123456
+      MYSQL_DATABASE: super_biz_agent
+      MYSQL_USER: superbiz
+      MYSQL_PASSWORD: superbiz123
+      TZ: Asia/Shanghai
+    ports:
+      - "3306:3306"
+    volumes:
+      - mysql-data:/var/lib/mysql
+      - ./docker/mysql/init:/docker-entrypoint-initdb.d
+    command: --character-set-server=utf8mb4 --collation-server=utf8mb4_unicode_ci
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  # Redis 缓存
+  redis:
+    image: redis:7-alpine
+    container_name: superbiz-redis
+    restart: always
+    ports:
+      - "6379:6379"
+    volumes:
+      - redis-data:/data
+    command: redis-server --appendonly yes --requirepass redis123
+    healthcheck:
+      test: ["CMD", "redis-cli", "ping"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+
+  # Milvus 向量数据库（Standalone 模式）
+  # 注意：生产环境建议使用 Zilliz Cloud 或 Milvus 集群
+  etcd:
+    image: quay.io/coreos/etcd:v3.5.5
+    container_name: superbiz-etcd
+    environment:
+      - ETCD_AUTO_COMPACTION_MODE=revision
+      - ETCD_AUTO_COMPACTION_RETENTION=1000
+      - ETCD_QUOTA_BACKEND_BYTES=4294967296
+      - ETCD_SNAPSHOT_COUNT=50000
+    volumes:
+      - etcd-data:/etcd
+    command: etcd -advertise-client-urls=http://127.0.0.1:2379 -listen-client-urls http://0.0.0.0:2379 --data-dir /etcd
+    healthcheck:
+      test: ["CMD", "etcdctl", "endpoint", "health"]
+      interval: 30s
+      timeout: 20s
+      retries: 3
+
+  minio:
+    image: minio/minio:RELEASE.2023-03-20T20-16-18Z
+    container_name: superbiz-minio
+    environment:
+      MINIO_ACCESS_KEY: minioadmin
+      MINIO_SECRET_KEY: minioadmin
+    volumes:
+      - minio-data:/minio_data
+    command: minio server /minio_data --console-address ":9001"
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:9000/minio/health/live"]
+      interval: 30s
+      timeout: 20s
+      retries: 3
+
+  milvus:
+    image: milvusdb/milvus:v2.3.3
+    container_name: superbiz-milvus
+    depends_on:
+      - etcd
+      - minio
+    environment:
+      ETCD_ENDPOINTS: etcd:2379
+      MINIO_ADDRESS: minio:9000
+    volumes:
+      - milvus-data:/var/lib/milvus
+    ports:
+      - "19530:19530"
+      - "9091:9091"
+    command: ["milvus", "run", "standalone"]
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost:9091/healthz"]
+      interval: 30s
+      start_period: 90s
+      timeout: 20s
+      retries: 3
+
+volumes:
+  mysql-data:
+  redis-data:
+  etcd-data:
+  minio-data:
+  milvus-data:
+
+networks:
+  default:
+    name: superbiz-network