fix: 修复学生导入模板下载功能

使用 axios (request) 替代 fetch，走 Vite 代理正确转发请求

frontend/ruoyi-ui/src/views/business/student/components/ImportDialog.vue

@@ -87,6 +87,7 @@ import { Download, UploadFilled } from '@element-plus/icons-vue'
 import { ElMessage } from 'element-plus'
 import { computed, ref } from 'vue'
 import { getToken } from '@/utils/auth'
+import request from '@/utils/request'
 
 const emit = defineEmits(['success'])
 
@@ -112,20 +113,15 @@ const uploadHeaders = computed(() => {
 const handleDownloadTemplate = async () => {
   downloadLoading.value = true
   try {
-    const baseApi = import.meta.env.VITE_APP_BASE_API || ''
-    // 使用 fetch 下载文件
-    const response = await fetch(`${baseApi}/business/student/template`, {
-      method: 'GET',
-      headers: {
-        'Authorization': 'Bearer ' + getToken()
-      }
+    // 使用 axios 下载文件（走 Vite 代理）
+    const response = await request({
+      url: '/business/student/template',
+      method: 'get',
+      responseType: 'blob'
     })
     
-    if (!response.ok) {
-      throw new Error('下载失败')
-    }
-    
-    const blob = await response.blob()
+    // response 就是 blob 数据
+    const blob = new Blob([response], { type: 'application/vnd.openxmlformats-officedocument.spreadsheetml.sheet' })
     const url = window.URL.createObjectURL(blob)
     const link = document.createElement('a')
     link.href = url