feat: 全量功能模块开发与集成测试修复

- 新增后端模块：Alert、APIAsset、Compliance、Lineage、Masking、Risk、SchemaChange、Unstructured、Watermark
- 新增前端模块页面与API接口
- 新增Alembic迁移脚本(002-014)覆盖全量业务表
- 新增测试数据生成脚本与集成测试脚本
- 修复metadata模型JSON类型导入缺失导致启动失败的问题
- 修复前端Alert/APIAsset页面request模块路径错误
- 更新docker-compose与开发计划文档

backend/.env.example

@@ -0,0 +1,29 @@
+# Database
+DATABASE_URL=postgresql+psycopg2://pdg:pdg_secret_2024@localhost:5432/prop_data_guard
+REDIS_URL=redis://localhost:6379/0
+
+# Security
+SECRET_KEY=prop-data-guard-super-secret-key-change-in-production
+# Fernet-compatible encryption key for database passwords (32 bytes, base64 url-safe).
+# Generate one with: python -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"
+# IMPORTANT: Keep this key safe and consistent across all backend instances.
+DB_ENCRYPTION_KEY=
+
+# MinIO
+MINIO_ENDPOINT=localhost:9000
+MINIO_ACCESS_KEY=pdgminio
+MINIO_SECRET_KEY=pdgminio_secret_2024
+MINIO_SECURE=false
+MINIO_BUCKET_NAME=pdg-files
+
+# CORS
+CORS_ORIGINS=["http://localhost:5173", "http://127.0.0.1:5173"]
+
+# Auth
+ACCESS_TOKEN_EXPIRE_MINUTES=30
+REFRESH_TOKEN_EXPIRE_DAYS=7
+
+# Default superuser (created on first startup)
+FIRST_SUPERUSER_USERNAME=admin
+FIRST_SUPERUSER_PASSWORD=admin123
+FIRST_SUPERUSER_EMAIL=admin@datapo.com