feat(FileTree): 为文件树节点添加类型化图标和颜色

- 使用 `#icon` 插槽为树节点添加自定义图标组件
- 重构图标和颜色逻辑，使用 `FILE_TYPE_CONFIG` 对象集中管理文件类型配置
- 为文件夹添加展开/收起状态的不同图标，并使用黄色区分
- 调整树节点标题的字体大小和行高以改善视觉一致性

src/components/FileTree.vue

@@ -42,6 +42,12 @@
         :load-data="onLoadData"
         @select="onSelect"
       >
+        <template #icon="{ dataRef, expanded }">
+          <component 
+            :is="getFileIcon(dataRef.name, dataRef.type, expanded)"
+            :style="{ color: getFileIconColor(dataRef.name, dataRef.type), fontSize: '18px', marginRight: '6px' }"
+          />
+        </template>
         <template #title="{ dataRef }">
           <a-dropdown :trigger="['contextmenu']">
             <span class="tree-node-title" :title="dataRef.name">{{ dataRef.name }}</span>
@@ -90,7 +96,20 @@
 
 <script setup>
 import { computed, ref, watch } from 'vue';
-import { EyeInvisibleOutlined, EyeOutlined, ReloadOutlined, SearchOutlined } from '@ant-design/icons-vue';
+import { 
+  EyeInvisibleOutlined, 
+  EyeOutlined, 
+  ReloadOutlined, 
+  SearchOutlined,
+  FileOutlined,
+  FileMarkdownOutlined,
+  FileImageOutlined,
+  FilePdfOutlined,
+  CodeOutlined,
+  FileTextOutlined,
+  FolderFilled,
+  FolderOpenFilled
+} from '@ant-design/icons-vue';
 import { useFileTree } from '../composables/useFileTree';
 import { useTabs } from '../composables/useTabs';
 import { useConfig } from '../composables/useConfig';
@@ -189,71 +208,51 @@ const onSelect = (keys, { node }) => {
 
 const isMdFile = (name) => name && name.toLowerCase().endsWith('.md');
 
-const getFileIcon = (fileName) => {
-  if (!fileName) return FileOutlined;
-  const ext = fileName.split('.').pop().toLowerCase();
-  switch (ext) {
-    case 'md':
-    case 'markdown':
-      return FileMarkdownOutlined;
-    case 'png':
-    case 'jpg':
-    case 'jpeg':
-    case 'gif':
-    case 'webp':
-    case 'svg':
-    case 'ico':
-      return FileImageOutlined;
-    case 'pdf':
-      return FilePdfOutlined;
-    case 'js':
-    case 'json':
-    case 'ts':
-    case 'css':
-    case 'html':
-    case 'vue':
-    case 'xml':
-    case 'yaml':
-    case 'yml':
-      return CodeOutlined;
-    case 'txt':
-    case 'log':
-      return FileTextOutlined;
-    default:
-      return FileOutlined;
-  }
+const FILE_TYPE_CONFIG = {
+  md: { icon: FileMarkdownOutlined, color: '#1890ff' },
+  markdown: { icon: FileMarkdownOutlined, color: '#1890ff' },
+  png: { icon: FileImageOutlined, color: '#722ed1' },
+  jpg: { icon: FileImageOutlined, color: '#722ed1' },
+  jpeg: { icon: FileImageOutlined, color: '#722ed1' },
+  gif: { icon: FileImageOutlined, color: '#722ed1' },
+  webp: { icon: FileImageOutlined, color: '#722ed1' },
+  svg: { icon: FileImageOutlined, color: '#722ed1' },
+  ico: { icon: FileImageOutlined, color: '#722ed1' },
+  pdf: { icon: FilePdfOutlined, color: '#f5222d' },
+  js: { icon: CodeOutlined, color: '#52c41a' },
+  json: { icon: CodeOutlined, color: '#52c41a' },
+  ts: { icon: CodeOutlined, color: '#52c41a' },
+  css: { icon: CodeOutlined, color: '#52c41a' },
+  html: { icon: CodeOutlined, color: '#52c41a' },
+  vue: { icon: CodeOutlined, color: '#52c41a' },
+  xml: { icon: CodeOutlined, color: '#52c41a' },
+  yaml: { icon: CodeOutlined, color: '#52c41a' },
+  yml: { icon: CodeOutlined, color: '#52c41a' },
+  txt: { icon: FileTextOutlined, color: 'inherit' },
+  log: { icon: FileTextOutlined, color: 'inherit' },
 };
 
-const getFileIconColor = (fileName) => {
-  if (!fileName) return 'inherit';
-  const ext = fileName.split('.').pop().toLowerCase();
-  switch (ext) {
-    case 'md':
-    case 'markdown':
-      return '#1890ff';
-    case 'png':
-    case 'jpg':
-    case 'jpeg':
-    case 'gif':
-    case 'webp':
-    case 'svg':
-    case 'ico':
-      return '#722ed1';
-    case 'pdf':
-      return '#f5222d';
-    case 'js':
-    case 'json':
-    case 'ts':
-    case 'css':
-    case 'html':
-    case 'vue':
-    case 'xml':
-    case 'yaml':
-    case 'yml':
-      return '#52c41a';
-    default:
-      return 'inherit';
+const getFileExtension = (fileName) => {
+  if (!fileName) return '';
+  const lastDotIndex = fileName.lastIndexOf('.');
+  if (lastDotIndex === -1 || lastDotIndex === 0) return '';
+  return fileName.substring(lastDotIndex + 1).toLowerCase();
+};
+
+const getFileIcon = (fileName, type, expanded) => {
+  if (type === 'directory') {
+    return expanded ? FolderOpenFilled : FolderFilled;
   }
+  const ext = getFileExtension(fileName);
+  return FILE_TYPE_CONFIG[ext]?.icon || FileOutlined;
+};
+
+const getFileIconColor = (fileName, type) => {
+  if (type === 'directory') {
+    return '#ffc60a'; // 文件夹黄色
+  }
+  const ext = getFileExtension(fileName);
+  return FILE_TYPE_CONFIG[ext]?.color || 'inherit';
 };
 
 const isPinned = (path) => config.pinnedFiles.includes(path);
@@ -431,13 +430,15 @@ const handleModalOk = async () => {
   flex: 1; /* 让文字占满剩余空间 */
   min-width: 0; /* 关键：允许在 flex 容器中收缩，从而触发省略号 */
   margin-left: 4px; /* spacing between icon and text */
+  font-size: 16px;
+  line-height: 28px;
 }
 
 :deep(.ant-tree-node-content-wrapper) {
   display: flex;
   align-items: center;
   overflow: hidden;
-  min-height: 28px; /* improve touch target / spacing */
+  min-height: 32px; /* improve touch target / spacing */
   padding: 0 4px;
   border-radius: 4px;
   transition: all 0.2s;