feat(team-admin): TeamAdminLayout 加消息中心铃铛 + 主题切换 — 跟超管侧栏对齐

之前团管侧栏 footer 只有头像 + 退出,缺这两个常用按钮。
观察者团管访问 /admin/assets 走 AdminLayout 是有这俩的,
团管在 /team/* 反而没有,体验不一致。

照搬 AdminLayout 同款实现:
- 消息中心铃铛:60s 轮询 + visibilitychange 立即拉,有未读右上角红点
- 主题切换:深色/浅色切换,月亮/太阳 SVG

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

web/src/pages/TeamAdminLayout.tsx

@@ -1,6 +1,8 @@
 import { NavLink, Outlet, useNavigate } from 'react-router-dom';
 import { useAuthStore } from '../store/auth';
-import { useState } from 'react';
+import { useThemeStore } from '../store/theme';
+import { useNotificationStore } from '../store/notification';
+import { useState, useEffect } from 'react';
 import logoImg from '../assets/logo_32.png';
 import styles from './AdminLayout.module.css';
 
@@ -14,9 +16,23 @@ const navItems = [
 export function TeamAdminLayout() {
   const user = useAuthStore((s) => s.user);
   const logout = useAuthStore((s) => s.logout);
+  const theme = useThemeStore((s) => s.theme);
+  const toggleTheme = useThemeStore((s) => s.toggleTheme);
+  const unreadCount = useNotificationStore((s) => s.unreadCount);
+  const fetchUnreadCount = useNotificationStore((s) => s.fetchUnreadCount);
   const navigate = useNavigate();
   const [collapsed, setCollapsed] = useState(false);
 
+  // 60s 轮询未读数 + tab 重新可见时立即拉一次(和 AdminLayout 一致)
+  useEffect(() => {
+    if (!user) return;
+    fetchUnreadCount();
+    const tick = setInterval(fetchUnreadCount, 60_000);
+    const onVis = () => { if (!document.hidden) fetchUnreadCount(); };
+    document.addEventListener('visibilitychange', onVis);
+    return () => { clearInterval(tick); document.removeEventListener('visibilitychange', onVis); };
+  }, [user, fetchUnreadCount]);
+
   const handleLogout = () => {
     logout();
     navigate('/login', { replace: true });
@@ -80,6 +96,50 @@ export function TeamAdminLayout() {
         </nav>
 
         <div className={styles.sidebarFooter}>
+          {/* 消息中心铃铛 — 有未读时右上角红点 */}
+          <button
+            className={styles.themeToggle}
+            onClick={() => navigate('/notifications')}
+            title={unreadCount > 0 ? `${unreadCount} 条未读消息` : '消息中心'}
+            aria-label="消息中心"
+            style={{ position: 'relative' }}
+          >
+            <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+              <path d="M18 8A6 6 0 0 0 6 8c0 7-3 9-3 9h18s-3-2-3-9" />
+              <path d="M13.73 21a2 2 0 0 1-3.46 0" />
+            </svg>
+            {!collapsed && <span>消息中心{unreadCount > 0 ? ` (${unreadCount})` : ''}</span>}
+            {unreadCount > 0 && (
+              <span style={{
+                position: 'absolute',
+                top: 6, left: collapsed ? 22 : 22,
+                width: 8, height: 8, borderRadius: '50%',
+                background: 'var(--color-danger)',
+                boxShadow: '0 0 0 2px var(--color-bg-sidebar)',
+              }} />
+            )}
+          </button>
+
+          {/* 主题切换 — 月亮/太阳 SVG */}
+          <button
+            className={styles.themeToggle}
+            onClick={toggleTheme}
+            title={theme === 'dark' ? '切换到浅色主题' : '切换到深色主题'}
+            aria-label={theme === 'dark' ? '切换到浅色主题' : '切换到深色主题'}
+          >
+            {theme === 'dark' ? (
+              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+                <path d="M21 12.79A9 9 0 1 1 11.21 3 7 7 0 0 0 21 12.79z" />
+              </svg>
+            ) : (
+              <svg width="16" height="16" viewBox="0 0 24 24" fill="none" stroke="currentColor" strokeWidth="2" strokeLinecap="round" strokeLinejoin="round">
+                <circle cx="12" cy="12" r="4" />
+                <path d="M12 2v2M12 20v2M4.93 4.93l1.41 1.41M17.66 17.66l1.41 1.41M2 12h2M20 12h2M4.93 19.07l1.41-1.41M17.66 6.34l1.41-1.41" />
+              </svg>
+            )}
+            {!collapsed && <span>{theme === 'dark' ? '浅色' : '深色'}</span>}
+          </button>
+
           <div className={styles.userInfo}>
             <div className={styles.userAvatar}>{user?.username.charAt(0).toUpperCase()}</div>
             {!collapsed && (