Refine chat tool status dedupe (#786)

Co-authored-by: zuolingxuan <zuolingxuan@bytedance.com>

tests/unit/chat-message.test.tsx

@@ -0,0 +1,33 @@
+import { describe, expect, it } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { ChatMessage } from '@/pages/Chat/ChatMessage';
+import type { RawMessage } from '@/stores/chat';
+
+describe('ChatMessage attachment dedupe', () => {
+  it('keeps attachment-only assistant replies visible even when process attachments are suppressed', () => {
+    const message: RawMessage = {
+      role: 'assistant',
+      content: [],
+      _attachedFiles: [
+        {
+          fileName: 'artifact.png',
+          mimeType: 'image/png',
+          fileSize: 0,
+          preview: '/tmp/artifact.png',
+          filePath: '/tmp/artifact.png',
+          source: 'tool-result',
+        },
+      ],
+    };
+
+    render(
+      <ChatMessage
+        message={message}
+        showThinking={false}
+        suppressProcessAttachments
+      />,
+    );
+
+    expect(screen.getByAltText('artifact.png')).toBeInTheDocument();
+  });
+});