fix(auth): 优化 ProtectedRoute 加载状态和逻辑

- 使用 PageLoader 替换白色加载背景
- 未登录时不渲染子组件，显示加载状态
- 登录成功后才显示受保护内容

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/components/ProtectedRouteRedirect.js

@@ -2,28 +2,15 @@
 // 未登录时跳转到首页，用于三级页面（详情页）
 import React from 'react';
 import { Navigate } from 'react-router-dom';
-import { Box, VStack, Spinner, Text } from '@chakra-ui/react';
 import { useAuth } from '../contexts/AuthContext';
+import PageLoader from './Loading/PageLoader';
 
 const ProtectedRouteRedirect = ({ children }) => {
   const { isAuthenticated, isLoading, user } = useAuth();
 
   // 显示加载状态
   if (isLoading) {
-    return (
-      <Box
-        height="100vh"
-        display="flex"
-        alignItems="center"
-        justifyContent="center"
-        bg="gray.50"
-      >
-        <VStack spacing={4}>
-          <Spinner size="xl" color="blue.500" thickness="4px" />
-          <Text fontSize="lg" color="gray.600">正在验证登录状态...</Text>
-        </VStack>
-      </Box>
-    );
+    return <PageLoader message="正在验证登录状态..." />;
   }
 
   // 未登录，直接跳转到首页