fix: keep teacher runtime prompts within interface boundary

tests/unit/coding-teacher-ui.test.tsx

@@ -158,6 +158,29 @@ describe('teacher side chat', () => {
     expect(details?.querySelector('script')).toBeNull();
   });
 
+  it('shows the format error alongside the preserved reply while keeping excess shortcuts noninteractive', async () => {
+    const response = '先看看摸头会带来什么变化。';
+    const quickReplies = ['看懂规则｜摸头会改变什么？', '想想作用｜我们聊聊摸头。', '试试结果｜怎样看出变化？', '换个话题｜我想聊别的地方。'];
+    const replyParseError = '快捷回复超过当前界面最多 3 条的限制，正文已保留，快捷回复未展示。';
+    const raw = '\n' + JSON.stringify({ reply: response, quickReplies }, null, 2) + '\n';
+    api.read.mockResolvedValue({ ...first, requests: [suggestionsRequest({
+      presentation: 'reply-v1', response, suggestedQuestions: [], replyParseError, unparsedResponse: raw,
+    })] });
+    render(<TeacherChatPanel projectId="p" sourceId="c" />);
+    await ready();
+
+    expect(screen.getByText(response)).toBeVisible();
+    expect(screen.getByText(replyParseError)).toBeVisible();
+    for (const shortcut of quickReplies) {
+      expect(screen.queryByRole('button', { name: shortcut, exact: true })).not.toBeInTheDocument();
+    }
+    const details = screen.getByText('查看收到的原始内容').closest('details');
+    expect(details).not.toHaveAttribute('open');
+    expect(details?.querySelector('pre')?.textContent).toBe(raw);
+    expect(screen.getByLabelText('向智能体提问')).toBeEnabled();
+    expect(api.send).not.toHaveBeenCalled();
+  });
+
   it('renders formulas and preserves code escapes while rejecting executable links and HTML', async () => {
     api.read.mockResolvedValue({ ...first, requests: [request({
       response: '$E=mc^2$\n\n```js\nconst value = "\\n";\n```\n\n[危险](javascript:alert)\n\n<script>alert(1)</script>\n\n![本地图片](file:///C:/secret.png)\n\n![坏图片](https://example.com/missing.png)',
@@ -591,6 +614,22 @@ describe('teacher side chat', () => {
 
 
 describe('legacy discussion history compatibility', () => {
+  it('shows every historical shortcut even when the old reply has more than three', async () => {
+    const shortcuts = ['看懂规则｜摸头会改变什么？', '想想作用｜我们聊聊摸头。', '试试结果｜怎样看出变化？', '换个话题｜我想聊别的地方。'];
+    api.read.mockResolvedValue({ ...first, requests: [request({
+      presentation: 'discussion-v1', response: '这些是之前留下的讨论入口。', suggestedQuestions: shortcuts,
+    })] });
+    render(<TeacherChatPanel projectId="p" sourceId="c" />);
+    await ready();
+
+    expect(screen.getByText('这些是之前留下的讨论入口。')).toBeVisible();
+    for (const shortcut of shortcuts) {
+      expect(screen.getByRole('button', { name: shortcut, exact: true })).toBeEnabled();
+    }
+    expect(screen.queryByText('查看收到的原始内容')).not.toBeInTheDocument();
+    expect(api.send).not.toHaveBeenCalled();
+  });
+
   const contents = [
     { kind: 'ideas', title: '旧想法组件', items: [{ id: 'dog', text: '养只小狗', state: 'kept' }] },
     { kind: 'structure', title: '旧结构组件', nodes: [{ id: 'dog', label: '照顾小狗' }] },