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/review/script/[id]/page.tsx

@@ -7,6 +7,7 @@ import { Button } from '@/components/ui/Button'
 import { Modal, ConfirmModal } from '@/components/ui/Modal'
 import { SuccessTag, WarningTag, ErrorTag, PendingTag } from '@/components/ui/Tag'
 import { ReviewSteps, getBrandReviewSteps } from '@/components/ui/ReviewSteps'
+import { useToast } from '@/components/ui/Toast'
 import {
   ArrowLeft,
   FileText,
@@ -99,6 +100,7 @@ function ReviewProgressBar({ taskStatus }: { taskStatus: string }) {
 export default function BrandScriptReviewPage() {
   const router = useRouter()
   const params = useParams()
+  const toast = useToast()
   const [showApproveModal, setShowApproveModal] = useState(false)
   const [showRejectModal, setShowRejectModal] = useState(false)
   const [rejectReason, setRejectReason] = useState('')
@@ -109,17 +111,17 @@ export default function BrandScriptReviewPage() {
 
   const handleApprove = () => {
     setShowApproveModal(false)
-    alert('审核通过！')
+    toast.success('审核通过')
     router.push('/brand/review')
   }
 
   const handleReject = () => {
     if (!rejectReason.trim()) {
-      alert('请填写驳回原因')
+      toast.error('请填写驳回原因')
       return
     }
     setShowRejectModal(false)
-    alert('已驳回')
+    toast.success('已驳回')
     router.push('/brand/review')
   }