Show the teacher refresh button as an icon only

src/pages/Chat/TeacherCompanion.tsx

@@ -58,7 +58,6 @@ export function TeacherCompanion({ companion, open, onOpen, onToggle, bubbleRef,
         title={refreshMessage || '刷新智能体'} disabled={loading || companion.refreshing} aria-busy={companion.refreshing}
         onMouseDown={(event) => event.preventDefault()} onClick={() => { setIntroductionId(null); void companion.refresh(); }}>
         <RefreshCw className={`h-3.5 w-3.5 shrink-0 ${companion.refreshing ? 'animate-spin motion-reduce:animate-none' : ''}`} aria-hidden="true" />
-        <span>{companion.refreshing ? '刷新中' : companion.refreshStatus === 'error' ? '刷新失败' : companion.refreshStatus === 'success' ? '已更新' : '刷新'}</span>
       </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">

src/pages/Chat/classroom-workspace.css

@@ -110,7 +110,7 @@
 @keyframes teacher-introduction-in { from { opacity: 0; } to { opacity: 1; } }
 @media (prefers-reduced-motion: reduce) { .teacher-introduction { animation: none; } }
 .consultation-agent-tabs { display: flex; align-items: center; gap: 4px; min-width: 0; max-width: 100%; overflow-x: auto; scrollbar-width: thin; }
-.consultation-agents-refresh { display: flex; align-items: center; justify-content: center; gap: 5px; flex-shrink: 0; width: 76px; height: 32px; border: 1px solid #dce4d5; border-radius: 8px; color: #526348; background: #f7f9f3; font-size: 12px; white-space: nowrap; cursor: pointer; transition: background 150ms; }
+.consultation-agents-refresh { display: flex; align-items: center; justify-content: center; flex-shrink: 0; width: 32px; height: 32px; border: 1px solid #dce4d5; border-radius: 8px; color: #526348; background: #f7f9f3; cursor: pointer; transition: background 150ms; }
 .consultation-agents-refresh:hover:not(:disabled) { background: #eaf0e1; }
 .consultation-agents-refresh:disabled { cursor: default; opacity: .6; }
 .consultation-agent-tabs .teacher-companion-person { flex-shrink: 0; }