添加 vue-router 依赖并配置路由，重构登录组件，完善 HTTP 请求拦截器以支持 token 刷新机制

src/components/PermissionDenied.vue

@@ -0,0 +1,37 @@
+<template>
+  <div class="permission-denied">
+    <el-result
+      icon="warning"
+      title="权限不足"
+      sub-title="您没有访问此页面的权限，请联系管理员"
+    >
+      <template #extra>
+        <el-button type="primary" @click="goBack">返回上一页</el-button>
+        <el-button @click="goHome">返回首页</el-button>
+      </template>
+    </el-result>
+  </div>
+</template>
+
+<script setup>
+import { useRouter } from 'vue-router'
+
+const router = useRouter()
+
+function goBack() {
+  router.go(-1)
+}
+
+function goHome() {
+  router.push({ name: 'Dashboard' })
+}
+</script>
+
+<style scoped>
+.permission-denied {
+  display: flex;
+  justify-content: center;
+  align-items: center;
+  min-height: 400px;
+}
+</style>