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}>

src/pages/Chat/classroom-workspace.css

@@ -113,20 +113,18 @@
 .teacher-companion-actions button:hover { text-decoration: underline; text-underline-offset: 4px; }
 .teacher-companion-speaker { flex-shrink: 0; width: 48px; height: 48px; margin-top: 5px; border-radius: 8px; }
 .teacher-companion-speaker img { width: 100%; height: 100%; object-fit: contain; image-rendering: pixelated; filter: drop-shadow(0 3px 1px #33485820); }
-.teacher-welcome-presence { position: absolute; top: calc(100% + 12px); right: 0; z-index: 90; width: 340px; max-width: calc(100vw - 40px); padding: 6px; border-radius: 18px; background: #fffdf8; box-shadow: 0 8px 24px #30465f12; }
-.teacher-welcome-heading { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 0 8px 4px; color: #6a7463; font-size: 12px; }
-.teacher-welcome-heading button { min-height: 32px; padding: 0 4px; color: #4d663c; border-radius: 8px; cursor: pointer; }
-.teacher-welcome-heading button:hover { background: #eef1e8; }
+.teacher-welcome-presence { position: absolute; top: calc(100% + 12px); right: 0; z-index: 90; width: 340px; max-width: calc(100vw - 40px); }
 .teacher-welcome-list { display: grid; gap: 10px; max-height: min(440px, calc(100vh - 200px)); overflow-y: auto; overscroll-behavior: contain; padding: 4px 6px 8px; scrollbar-width: thin; }
 .teacher-welcome-card { --welcome-fill: #fff3ce; --welcome-edge: #efddb0; display: flex; align-items: flex-start; gap: 10px; min-width: 0; animation: teacher-welcome-arrive 220ms ease-out backwards; animation-delay: var(--welcome-delay, 0ms); }
 .teacher-welcome-card[data-tone="1"] { --welcome-fill: #edf5ff; --welcome-edge: #d7e5f5; }
 .teacher-welcome-card[data-tone="2"] { --welcome-fill: #f3edfc; --welcome-edge: #e5d9f5; }
 .teacher-welcome-avatar { flex-shrink: 0; width: 42px; height: 44px; margin-top: 8px; padding: 2px; border: 1px solid var(--welcome-edge); border-radius: 14px; background: #fff; box-shadow: 0 3px 0 var(--welcome-edge); cursor: pointer; }
 .teacher-welcome-avatar img { width: 100%; height: 100%; object-fit: cover; border-radius: 11px; }
-.teacher-welcome-bubble { position: relative; flex: 1; min-width: 0; border: 1px solid var(--welcome-edge); border-radius: 17px 17px 17px 6px; background: var(--welcome-fill); box-shadow: 0 2px 0 var(--welcome-edge); }
-.teacher-welcome-bubble::before { content: ''; position: absolute; top: 23px; left: -5px; width: 8px; height: 8px; transform: rotate(45deg); border-left: 1px solid var(--welcome-edge); border-bottom: 1px solid var(--welcome-edge); background: var(--welcome-fill); }
-.teacher-welcome-open { display: flex; flex-direction: column; gap: 6px; width: 100%; min-width: 0; padding: 12px; border-radius: inherit; color: #34465c; text-align: left; cursor: pointer; }
-.teacher-welcome-open:hover { background: #ffffff40; }
+.teacher-welcome-bubble { position: relative; flex: 1; min-width: 0; }
+.teacher-welcome-open::before { content: ''; position: absolute; top: 23px; left: -5px; width: 8px; height: 8px; transform: rotate(45deg); border-left: 1px solid var(--welcome-edge); border-bottom: 1px solid var(--welcome-edge); background: var(--welcome-fill); }
+.teacher-welcome-open { position: relative; display: flex; flex-direction: column; gap: 6px; width: 100%; min-width: 0; padding: 12px; border: 1px solid var(--welcome-edge); border-radius: 17px 17px 17px 6px; background: var(--welcome-fill); box-shadow: 0 2px 0 var(--welcome-edge); color: #34465c; text-align: left; cursor: pointer; }
+.teacher-welcome-open:hover { filter: brightness(1.015); }
+.teacher-welcome-open:focus-visible, .teacher-welcome-dismiss:focus-visible, .teacher-welcome-avatar:focus-visible { outline: 2px solid #547ab0; outline-offset: 3px; }
 .teacher-welcome-name { padding-right: 20px; font-size: 13px; font-weight: 600; line-height: 19px; overflow-wrap: anywhere; }
 .teacher-welcome-text { display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; overflow-wrap: anywhere; white-space: pre-wrap; font-size: 13px; line-height: 1.6; }
 .teacher-welcome-action { display: inline-flex; align-items: center; gap: 3px; color: #596b55; font-size: 11px; line-height: 18px; }

src/pages/Chat/use-teacher-companion.ts

@@ -358,7 +358,6 @@ export function useTeacherCompanion(options: Options) {
         || `我是${agent.definition.name}，一起聊聊你的想法吧。`,
       tone: index % 3,
     }]) : [];
-  const dismissWelcomes = () => dismissIntroductions(welcomes.map(item => item.agentId));
   const welcome = !visibleState.agents.length && topic?.role !== 'friend' && !options.teacherOpen && !visibleState.loading && visibleState.enabled && !visibleState.welcomeDismissed
     ? selectedDefinition?.welcome_message.trim() || null : null;
   return {
@@ -375,7 +374,6 @@ export function useTeacherCompanion(options: Options) {
     welcome,
     welcomes,
     dismissWelcome,
-    dismissWelcomes,
     bubbleVisible: Boolean(invitation || welcome || welcomes.length),
     checking: last?.intent === 'check-in' && ['preparing', 'running'].includes(last.status),
     dismiss,