fix missing type annotations for graphql query field arguments

app/graphql/context.py

@@ -7,7 +7,6 @@ from typing import List
 from collections import defaultdict
 from app.db import SessionLocal
 from app.models import WorkspaceMember
-from app.graphql.types import WorkspaceMemberType
 from typing import AsyncGenerator
 
 # 定义批量查询函数：接收一组 workspace ID 列表，返回相同长度的结果列表
@@ -32,6 +31,8 @@ class CustomContext(BaseContext):
         super().__init__(request)
         self.db = SessionLocal()
         self.request = request
+        
+        self.members_loader = DataLoader(load_fn=load_members_by_workspace_ids)
 
     async def get_current_user(self) -> User | None:
         # 复用现有的 auth 逻辑