prepare fastapi root layout for server deployment

app/models/audit.py

@@ -0,0 +1,25 @@
+from datetime import datetime
+
+from sqlalchemy import DateTime, Integer, JSON, String
+from sqlalchemy.orm import Mapped, mapped_column
+
+from app.db.base import Base
+
+
+class AuditLog(Base):
+    """审计日志模型：记录关键接口和安全相关元数据。"""
+
+    __tablename__ = "audit_logs"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True, autoincrement=True)
+    user_id: Mapped[str | None] = mapped_column(String(128), index=True, comment="Django用户中心ID")
+    tenant_id: Mapped[str | None] = mapped_column(String(128))
+    session_id: Mapped[int | None] = mapped_column(Integer, index=True)
+    action: Mapped[str] = mapped_column(String(64), nullable=False, index=True)
+    resource_type: Mapped[str] = mapped_column(String(64), nullable=False)
+    resource_id: Mapped[str | None] = mapped_column(String(128))
+    request_id: Mapped[str | None] = mapped_column(String(128))
+    ip_address: Mapped[str | None] = mapped_column(String(64))
+    user_agent: Mapped[str | None] = mapped_column(String(512))
+    metadata_: Mapped[dict | None] = mapped_column("metadata", JSON)
+    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, index=True)