修复audit_logs记录时主键缺失的问题

app/infra/db/metadata/models.py

@@ -1,5 +1,5 @@
 from datetime import datetime
-from uuid import UUID
+from uuid import UUID, uuid4
 
 from sqlalchemy import Boolean, DateTime, Integer, String, Text
 from sqlalchemy.dialects.postgresql import JSONB, UUID as PGUUID
@@ -95,7 +95,9 @@ class UserProjectMembership(Base):
 class AuditLog(Base):
     __tablename__ = "audit_logs"
 
-    id: Mapped[UUID] = mapped_column(PGUUID(as_uuid=True), primary_key=True)
+    id: Mapped[UUID] = mapped_column(
+        PGUUID(as_uuid=True), primary_key=True, default=uuid4
+    )
     user_id: Mapped[UUID | None] = mapped_column(
         PGUUID(as_uuid=True), nullable=True, index=True
     )