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/app/models/masking.py

@@ -0,0 +1,22 @@
+from datetime import datetime
+from sqlalchemy import Column, Integer, String, Boolean, DateTime, ForeignKey, JSON, Text
+from sqlalchemy.orm import relationship
+from app.core.database import Base
+
+
+class MaskingRule(Base):
+    __tablename__ = "masking_rule"
+
+    id = Column(Integer, primary_key=True, index=True)
+    name = Column(String(100), nullable=False)
+    level_id = Column(Integer, ForeignKey("data_level.id"), nullable=True)
+    category_id = Column(Integer, ForeignKey("category.id"), nullable=True)
+    algorithm = Column(String(20), nullable=False)  # mask, truncate, hash, generalize, replace
+    params = Column(JSON, default=dict)  # algorithm-specific params
+    is_active = Column(Boolean, default=True)
+    description = Column(Text)
+    created_at = Column(DateTime, default=datetime.utcnow)
+    updated_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow)
+
+    level = relationship("DataLevel")
+    category = relationship("Category")