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/projects/create/page.tsx

@@ -2,6 +2,7 @@
 
 import { useState } from 'react'
 import { useRouter } from 'next/navigation'
+import { useToast } from '@/components/ui/Toast'
 import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/Card'
 import { Button } from '@/components/ui/Button'
 import { Input } from '@/components/ui/Input'
@@ -40,6 +41,7 @@ const mockAgencies = [
 
 export default function CreateProjectPage() {
   const router = useRouter()
+  const toast = useToast()
   const [projectName, setProjectName] = useState('')
   const [deadline, setDeadline] = useState('')
   const [briefFile, setBriefFile] = useState<File | null>(null)
@@ -73,14 +75,14 @@ export default function CreateProjectPage() {
 
   const handleSubmit = async () => {
     if (!projectName.trim() || !deadline || !briefFile || selectedAgencies.length === 0 || !selectedPlatform) {
-      alert('请填写完整信息')
+      toast.error('请填写完整信息')
       return
     }
 
     setIsSubmitting(true)
     // 模拟提交
     await new Promise(resolve => setTimeout(resolve, 1500))
-    alert('项目创建成功！')
+    toast.success('项目创建成功！')
     router.push('/brand')
   }