feat(workflow): move conversation file content into metadata

api/app/controllers/memory_working_controller.py

@@ -8,6 +8,7 @@ from app.core.response_utils import success
 from app.db import get_db
 from app.dependencies import get_current_user
 from app.models import User
+from app.schemas import conversation_schema
 from app.schemas.response_schema import ApiResponse
 from app.services.conversation_service import ConversationService
 
@@ -90,11 +91,7 @@ def get_messages(
         conversation_id,
     )
     messages = [
-        {
-            "role": message.role,
-            "content": message.content,
-            "created_at": int(message.created_at.timestamp() * 1000),
-        }
+        conversation_schema.Message.model_validate(message)
         for message in messages_obj
     ]
     return success(data=messages, msg="get conversation history success")