fix: show teacher introductions as standalone clickable bubbles

src/pages/Chat/TeacherCompanion.tsx

@@ -62,9 +62,6 @@ export function TeacherCompanion({ companion, open, onOpen, onToggle, bubbleRef,
       </button>
       <span className="sr-only" role="status" aria-live="polite">{refreshMessage}</span>
       {!invitation && welcomes.length > 0 && <div ref={bubbleRef} className="teacher-welcome-presence" data-testid="teacher-welcomes" aria-label="认识这里的老师">
-        <div className="teacher-welcome-heading"><span>来认识一下</span>
-          <button type="button" onClick={companion.dismissWelcomes}>先自己试试</button>
-        </div>
         <div className="teacher-welcome-list">
           {welcomes.map((item, index) => <article key={item.agentId} className="teacher-welcome-card" data-agent-id={item.agentId}
             data-tone={item.tone} style={{ '--welcome-delay': `${Math.min(index, 4) * 180}ms` } as CSSProperties}>