fix: 修复知识库树形目录图标渲染为 [object Object]

frontend/src/views/Library.vue

@@ -1,5 +1,5 @@
 <script setup>
-import { computed, onMounted, reactive, ref } from 'vue'
+import { computed, h, onMounted, reactive, ref } from 'vue'
 import { message, Modal } from 'ant-design-vue'
 import {
   FolderOutlined,
@@ -108,14 +108,6 @@ function makeCategoryNode(cat, docs) {
   }
 }
 
-function h(type) {
-  return { render: () => _h(type) }
-}
-
-function _h(type) {
-  return type
-}
-
 const treeDataComputed = computed(() => buildTree())
 
 function handleTreeSelect(keys, info) {