feat: add creative welcome and external works square links

tests/e2e/fixtures/community-welcome.tsx

@@ -0,0 +1,51 @@
+import { useState, type ComponentProps } from 'react';
+import { createRoot } from 'react-dom/client';
+import { CodingChatBody } from '../../../src/pages/Chat/CodingChatBody';
+import { CodingStartHeading } from '../../../src/pages/Chat/CodingStartHeading';
+import { CodingComposer } from '../../../src/pages/Chat/CodingComposer';
+import { TeacherCompanion } from '../../../src/pages/Chat/TeacherCompanion';
+import { CommunityInvitation } from '../../../src/components/community/CommunityInvitation';
+import '../../../src/styles/globals.css';
+import '../../../src/pages/Chat/classroom-workspace.css';
+
+export function Layout() {
+  const [bubble, setBubble] = useState<HTMLDivElement | null>(null);
+  const [draft, setDraft] = useState('');
+  const [sent, setSent] = useState(false);
+  const [dismissed, setDismissed] = useState<string[]>([]);
+  const agents = ['架构工程师-陈宗琦', '产品工程师-Alice'].map((name, index) => ({
+    teacher_id: String(index), version: 1, is_default: index === 0,
+    definition: { config_id: String(index), name, avatar_id: 'avatar-06',
+      description: index === 0 ? '有什么编程问题想一起讨论？' : '陪你把天马行空的点子，变成能玩、能用、眼睛一亮的小作品。' },
+  }));
+  const companion = {
+    agents, selectedAgent: agents[0], definition: agents[0].definition, enabled: true,
+    unreadAgentIds: [], invitation: null, welcome: null, loading: false, error: null, checking: false,
+    refreshing: false, refreshStatus: 'idle', refresh: async () => {}, reloadCatalog: async () => {}, dismiss: () => {},
+    welcomes: new URLSearchParams(location.search).has('teachers') ? agents.flatMap((agent, index) => dismissed.includes(agent.teacher_id)
+      ? [] : [{ agentId: agent.teacher_id, definition: agent.definition, text: agent.definition.description, tone: index }]) : [],
+    dismissWelcome: (id: string) => setDismissed(values => [...values, id]),
+    dismissWelcomes: () => setDismissed(['0', '1']),
+  } as ComponentProps<typeof TeacherCompanion>['companion'];
+  return <div className="classroom-workspace flex h-screen flex-col bg-white">
+    <header className="relative z-50 flex h-12 shrink-0 items-center justify-end border-b px-3" data-testid="coding-conversation-header">
+      <span className="mr-auto min-w-0 truncate text-xs">测试项目 › 新对话</span>
+      <TeacherCompanion companion={companion} open={false} onOpen={() => {}} onToggle={() => {}} bubbleRef={setBubble} />
+    </header>
+    <main className="classroom-main flex min-h-0 min-w-0 flex-1 flex-col">
+      <div className="classroom-tabs" role="tablist"><button role="tab" aria-selected="true">操作对话</button><button role="tab">作品</button></div>
+      <CodingChatBody welcome={!sent} hidden={false} bubble={bubble}>
+        <div className="classroom-chat-view min-h-0 flex-1">{!sent ? <CodingStartHeading /> : <p>第一条消息已发送（测试）</p>}</div>
+        <div className="classroom-composer-view shrink-0">
+          <CodingComposer value={draft} editable canSend={Boolean(draft)} preparing={false} recovering={false}
+            runStatus="idle" mode="prompt" queue={{ items: [] }} error={null} recoverableError={false}
+            attachments={[]} submitting={false} placeholder="说说你的想法，接下来想做什么？" onChange={setDraft}
+            onModeChange={() => {}} onSubmit={() => { setSent(true); setDraft(''); }} onRecover={() => {}}
+            onAddFiles={() => {}} onRemoveAttachment={() => {}} />
+        </div>
+        {!sent && <CommunityInvitation />}
+      </CodingChatBody>
+    </main>
+  </div>;
+}
+createRoot(document.getElementById('root')!).render(<Layout />);