fix: 修复前端代码质量问题

- 创建 Toast 通知组件，替换所有 alert() 调用
- 修复 useReview hook 内存泄漏（setInterval 清理）
- 移除所有 console.error 和 console.log 语句
- 为复制操作失败添加用户友好的 toast 提示

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/app/brand/settings/page.tsx

@@ -5,6 +5,7 @@ import { useRouter } from 'next/navigation'
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/Card'
 import { Button } from '@/components/ui/Button'
 import { Modal } from '@/components/ui/Modal'
+import { useToast } from '@/components/ui/Toast'
 import {
   Bell,
   Shield,
@@ -32,6 +33,7 @@ import {
 
 export default function BrandSettingsPage() {
   const router = useRouter()
+  const toast = useToast()
   const [notifications, setNotifications] = useState({
     email: true,
     push: true,
@@ -95,7 +97,7 @@ export default function BrandSettingsPage() {
   ]
 
   const handleSave = () => {
-    alert('设置已保存')
+    toast.success('设置已保存')
   }
 
   const handleLogout = () => {
@@ -105,10 +107,10 @@ export default function BrandSettingsPage() {
 
   const handleChangePassword = () => {
     if (passwordForm.new !== passwordForm.confirm) {
-      alert('两次输入的密码不一致')
+      toast.error('两次输入的密码不一致')
       return
     }
-    alert('密码修改成功')
+    toast.success('密码修改成功')
     setShowPasswordModal(false)
     setPasswordForm({ current: '', new: '', confirm: '' })
   }
@@ -116,18 +118,18 @@ export default function BrandSettingsPage() {
   const handleEnable2FA = () => {
     setTwoFAEnabled(true)
     setShow2FAModal(false)
-    alert('双因素认证已启用')
+    toast.success('双因素认证已启用')
   }
 
   const handleChangeEmail = () => {
-    alert(`邮箱已更新为 ${newEmail}`)
+    toast.success(`邮箱已更新为 ${newEmail}`)
     setShowEmailModal(false)
     setNewEmail('')
     setEmailCode('')
   }
 
   const handleChangePhone = () => {
-    alert(`手机号已更新为 ${newPhone}`)
+    toast.success(`手机号已更新为 ${newPhone}`)
     setShowPhoneModal(false)
     setNewPhone('')
     setPhoneCode('')
@@ -139,11 +141,11 @@ export default function BrandSettingsPage() {
     await new Promise(resolve => setTimeout(resolve, 2000))
     setIsExporting(false)
     setShowExportModal(false)
-    alert('导出任务已创建，完成后将通知您下载')
+    toast.info('导出任务已创建，完成后将通知您下载')
   }
 
   const handleRemoveDevice = (deviceId: string) => {
-    alert('已移除该设备的登录状态')
+    toast.success('已移除该设备的登录状态')
   }
 
   return (