调整保存知识库标签的返回格式

agent/router/knowledge_base_router.py

@@ -54,6 +54,12 @@ class KnowledgeBaseResponse(BaseModel):
     @field_serializer('created_at', 'updated_at')
     def serialize_datetime(self, dt: datetime) -> str:
         return dt.strftime('%Y-%m-%d')
+        
+    @field_serializer('tags')
+    def serialize_tags(self, tags: str) -> Optional[List[str]]:
+        if tags:
+            return json.loads(tags)
+        return None
 
 
 class KnowledgeFileResponse(BaseModel):