fix: show teacher introductions as standalone clickable bubbles

tests/e2e/fixtures/community-welcome.tsx

@@ -25,7 +25,6 @@ export function Layout() {
     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="flex h-screen">
     {new URLSearchParams(location.search).has('sidebar') && <aside data-testid="project-sidebar" className="shrink-0 border-r p-4 text-sm" style={{ width: 210, background: '#f1f6fc' }}>我的项目</aside>}