fix: 修复未登录访问购物车页面报错不跳转登录页

- 给需要认证的路由添加 requiresAuth meta
- 修改 API 拦截器，401 错误时跳转登录页
- 路由守卫在用户未登录时拦截并跳转登录页
- 避免公开接口和登录/注册接口的 401 错误触发跳转

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

frontend/src/utils/request.ts

@@ -27,18 +27,18 @@ api.interceptors.response.use(
     const message = error.response?.data?.error || error.message || 'Request failed'
     if (error.response?.status === 401) {
       const isLoginRequest = error.config?.url?.includes('/auth/login')
-      if (isLoginRequest) {
+      const isRegisterRequest = error.config?.url?.includes('/auth/register')
+      const isPublicRequest = error.config?.url?.includes('/settings/public') || error.config?.url?.includes('/installed')
+
+      if (isLoginRequest || isRegisterRequest) {
         ElMessage.error(message)
-      } else {
-        const hadToken = !!localStorage.getItem('token')
+      } else if (!isPublicRequest) {
         localStorage.removeItem('token')
         localStorage.removeItem('user')
-        if (hadToken) {
-          ElMessage.error('登录已过期，请重新登录')
-          router.push('/login')
-        } else {
-          ElMessage.error(message)
-        }
+        ElMessage.error('请先登录')
+        router.push('/login')
+      } else {
+        ElMessage.error(message)
       }
     } else {
       ElMessage.error(message)