feat(web): add role-aware React dashboards

Add student and teacher dashboard variants backed by existing APIs, retain the administrative overview for management roles, and provide responsive navigation back to legacy routes that have not migrated yet.

web-react/src/layout/AppShell.tsx

@@ -23,17 +23,21 @@ export default function AppShell() {
   const logout = useAuthStore((state) => state.logout)
   const refreshUser = useAuthStore((state) => state.refreshUser)
   const [collapsed, setCollapsed] = useState(false)
+  const roles = user?.roles ?? []
+  const isStudentHome = roles.includes('Student') && !roles.some((role) => ['SuperAdmin', 'AcademicAdmin', 'CollegeAdmin', 'Counselor'].includes(role))
+  const isTeacherHome = roles.includes('Teacher') && !roles.some((role) => ['SuperAdmin', 'AcademicAdmin', 'CollegeAdmin', 'Counselor', 'Student'].includes(role))
+  const legacyBase = (import.meta.env.VITE_LEGACY_APP_URL ?? 'http://localhost:5255').replace(/\/$/, '')
 
   useEffect(() => { void refreshUser().catch(() => undefined) }, [refreshUser])
 
   const items = useMemo(() => [
-    { key: '/dashboard', icon: <AppstoreOutlined />, label: '教务总览' },
+    { key: '/dashboard', icon: <AppstoreOutlined />, label: isStudentHome ? '学习首页' : isTeacherHome ? '教学工作台' : '教务总览' },
     { key: '/account', icon: <IdcardOutlined />, label: '个人账户' },
     ...(user?.roles.includes('SuperAdmin')
       ? [{ key: '/users', icon: <SafetyCertificateOutlined />, label: '用户与权限' }]
       : []),
     { key: 'legacy', icon: <ExportOutlined />, label: '返回现有系统' },
-  ], [user?.roles])
+  ], [isStudentHome, isTeacherHome, user?.roles])
 
   const pageTitle = items.find((item) => location.pathname.startsWith(item.key))?.label ?? '迁移预览'
 
@@ -83,7 +87,7 @@ export default function AppShell() {
             <div className="shell-context"><span>当前工作区</span><strong>{pageTitle}</strong></div>
           </div>
           <div className="shell-user">
-            <Button type="text" aria-label="通知中心" icon={<BellOutlined />} />
+            <Button type="text" aria-label="通知中心" icon={<BellOutlined />} onClick={() => window.location.assign(`${legacyBase}/notifications`)} />
             <Tag color="geekblue">预览</Tag>
             <div className="shell-user__copy"><strong>{user?.displayName ?? '用户'}</strong><small>{user?.roles.join(' · ') || '正在读取权限'}</small></div>
             <Avatar style={{ background: '#54cfbd', color: '#163f43' }}>{user?.displayName?.slice(0, 1) ?? '明'}</Avatar>