Feature：Add a loading status to the agent canvas page. (#11733)

### What problem does this PR solve?

Feature：Add a loading status to the agent canvas page.

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/agent/chat/box.tsx

@@ -13,8 +13,9 @@ import {
 } from '@/hooks/use-agent-request';
 import { useFetchUserInfo } from '@/hooks/use-user-setting-request';
 import { buildMessageUuidWithRole } from '@/utils/chat';
-import { memo, useCallback } from 'react';
+import { memo, useCallback, useContext } from 'react';
 import { useParams } from 'umi';
+import { AgentChatContext } from '../context';
 import DebugContent from '../debug-content';
 import { useAwaitCompentData } from '../hooks/use-chat-logic';
 import { useIsTaskMode } from '../hooks/use-get-begin-query';
@@ -49,6 +50,9 @@ function AgentChatBox() {
     canvasId: canvasId as string,
   });
 
+  const { setDerivedMessages } = useContext(AgentChatContext);
+  setDerivedMessages?.(derivedMessages);
+
   const isTaskMode = useIsTaskMode();
 
   const handleUploadFile: NonNullable<FileUploadProps['onUpload']> =