prepare fastapi root layout for server deployment

app/services/audit_service.py

@@ -0,0 +1,38 @@
+from sqlalchemy.orm import Session
+
+from app.core.context import UserContext
+from app.models.audit import AuditLog
+from app.repositories.audit_repository import AuditRepository
+
+
+class AuditService:
+    """审计服务：统一记录关键接口调用和资源访问。"""
+
+    def __init__(self, db: Session) -> None:
+        self.db = db
+        self.repo = AuditRepository(db)
+
+    def log(
+        self,
+        ctx: UserContext,
+        action: str,
+        resource_type: str,
+        resource_id: str | None = None,
+        session_id: int | None = None,
+        metadata: dict | None = None,
+    ) -> None:
+        """审计写入：保存用户、动作、资源和请求元数据。"""
+        self.repo.create(
+            AuditLog(
+                user_id=ctx.user_id,
+                tenant_id=ctx.tenant_id,
+                session_id=session_id,
+                action=action,
+                resource_type=resource_type,
+                resource_id=resource_id,
+                request_id=ctx.request_id,
+                ip_address=ctx.ip_address,
+                user_agent=ctx.user_agent,
+                metadata_=metadata,
+            )
+        )