feat(chat): simplify teacher pane and color follow-up cards

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

@@ -1,4 +1,4 @@
-import { act, fireEvent, render, screen, waitFor, within } from '@testing-library/react';
+import { act, fireEvent, render, screen, waitFor } from '@testing-library/react';
 import { beforeEach, describe, expect, it, vi } from 'vitest';
 import { TeacherChatPanel } from '@/pages/Chat/TeacherChatPanel';
 import type { TeacherDefinition, TeacherRequest, TeacherSend, TeacherTopic } from '../../shared/coding-teacher';
@@ -96,31 +96,30 @@ async function ready() {
   await waitFor(() => expect(streams.has('first')).toBe(true));
 }
 describe('teacher side chat', () => {
-  it('keeps the panel header focused on identity and puts new topics inside expanded history', async () => {
+  it('opens directly into the consultation and puts new topics inside expanded history', async () => {
     render(<TeacherChatPanel projectId="p" sourceId="c" />);
     const history = await screen.findByRole('button', { name: '以往讨论' });
-    const header = screen.getByTestId('teacher-chat-panel').querySelector('header')!;
-    expect(within(header).getByRole('heading', { name: '智能体' })).toBeVisible();
-    expect(within(header).queryByRole('button')).not.toBeInTheDocument();
+    const panel = screen.getByRole('complementary', { name: '智能体咨询' });
+    expect(panel).toBeVisible();
+    expect(panel.querySelector('header')).toBeNull();
     expect(screen.queryByText('服务端简介')).not.toBeInTheDocument();
     expect(screen.queryByRole('button', { name: '智能体新话题' })).not.toBeInTheDocument();
     fireEvent.click(history);
     const newTopic = screen.getByRole('button', { name: '智能体新话题' });
     expect(newTopic).toBeEnabled();
     expect(newTopic).toHaveTextContent('新话题');
-    expect(header.contains(newTopic)).toBe(false);
     fireEvent.click(newTopic);
     await waitFor(() => expect(api.create).toHaveBeenCalledWith('p/agent-topics', undefined, undefined, 1));
     expect(api.send).not.toHaveBeenCalled();
   });
 
-  it('renders the pinned topic icon in the header and assistant messages', async () => {
+  it('renders the pinned topic icon with assistant messages', async () => {
     const icon = 'https://yuxi.example.test/api/storage/public/images/topic.png';
     api.read.mockResolvedValue({ ...first, definition: { ...definition, icon_url: icon }, requests: [request({ response: '继续原来的讨论' })] });
     const view = render(<TeacherChatPanel projectId="p" sourceId="c" />);
     await ready();
     const images = view.container.querySelectorAll('[data-testid="teacher-chat-panel"] img');
-    expect(images).toHaveLength(2);
+    expect(images).toHaveLength(1);
     for (const img of images) expect(img).toHaveAttribute('src', icon);
   });
 
@@ -311,9 +310,9 @@ describe('teacher side chat', () => {
     api.list.mockResolvedValue({ items: [], lastSelectedTopicId: null });
     api.catalog.mockResolvedValue({ items: [{ teacher_id: 'published', version: 2, is_default: true, definition: published }] });
     render(<TeacherChatPanel projectId="p" sourceId="c" />);
-    await screen.findByRole('heading', { name, exact: true });
+    const panel = await screen.findByRole('complementary', { name: `${name}咨询`, exact: true });
     expect(screen.queryByText('这是运营发布的简介')).not.toBeInTheDocument();
-    expect(within(screen.getByTestId('teacher-chat-panel').querySelector('header')!).queryByRole('button')).not.toBeInTheDocument();
+    expect(panel.querySelector('header')).toBeNull();
     expect(screen.getByText('服务端欢迎语')).toBeVisible();
     expect(screen.getByRole('button', { name: '服务端推荐问题' })).toBeEnabled();
     expect(screen.getByTestId('teacher-chat-panel').querySelector('img')?.src).toContain('avatar-09.png');
@@ -705,7 +704,7 @@ describe('merged cloud teacher classroom', () => {
     await screen.findByText('先看看玩家会做什么。');
     expect(api.create).toHaveBeenCalledWith('p/agent-topics', undefined, undefined, 9);
     expect(api.send.mock.calls[0][2]).toMatchObject({ sourceConversationId: 'c', presentation: 'discussion-v1' });
-    expect(screen.getByRole('heading', { name: '算法智能体' })).toBeVisible();
+    expect(screen.getByRole('complementary', { name: '算法智能体咨询' })).toBeVisible();
   });
 
   it('does not enable a disabled cloud topic through another teacher or an Enter shortcut', async () => {