refactor: 全面迁移 vue-class-component 至 Vue 3 Composition API

- 将所有页面组件从 class 语法重写为 <script setup> 风格
  - App.vue / Login.vue / Home.vue / Welcome.vue
  - api: Hitokoto.vue / HitokotoAdd.vue / Music.vue / PhotoWall.vue / SourceImage.vue
  - system: Article.vue / Statistics.vue / SystemConfig.vue / SystemConfigAdd.vue / SystemRole.vue / SystemUser.vue

- 新增 src/utils/http.ts：独立 axios 实例，含请求/响应拦截器，替代 vue-axios 插件
- baselist.ts：abstract class BaseList<T> → useBaseList<T>() 组合式函数
- types.ts：VForm 类型改用 Element Plus 原生 FormInstance
- main.ts：移除 vue-axios 及内联 axios 配置，路由守卫直接引用 store

- 依赖清理：移除 vue-class-component、vue-axios

src/utils/http.ts

@@ -0,0 +1,41 @@
+import axios from 'axios'
+import { ElMessage } from 'element-plus'
+import store from '@/store'
+import { router } from '@/router'
+
+const http = axios.create({
+  timeout: 10000
+})
+
+// 添加请求拦截器
+http.interceptors.request.use(config => {
+  const token = store.state.loginInfo.token
+  if (token !== null && config.headers) {
+    config.headers.token = token
+  }
+  return config
+}, err => {
+  ElMessage.error('请求超时，请稍后再试')
+  return Promise.reject(err)
+})
+
+http.interceptors.response.use(res => {
+  return res.data
+}, err => {
+  if (err.response.status >= 500) {
+    ElMessage.error('服务器内部错误')
+  } else if (err.response.status >= 400) {
+    if (typeof err.response.data.message === 'string') {
+      ElMessage.warning(err.response.data.message)
+    } else if (Array.isArray(err.response.data.message)) {
+      let message = err.response.data.message.join('<br/>')
+      ElMessage.warning(message)
+    }
+    if (err.response.status === 403) {
+      router.push('/login')
+    }
+  }
+  return Promise.reject(err)
+})
+
+export default http