feat(FileTree): 为文件树空白区域添加上下文菜单

新增对文件树空白区域的右键菜单支持，包含新建文件/文件夹、刷新和打开资源管理器选项

src/components/FileTree.vue

@@ -23,7 +23,8 @@
       <a-empty description="请选择目录" />
     </div>
 
-    <div v-else class="tree-content" ref="treeContentRef">
+    <a-dropdown v-else :trigger="['contextmenu']">
+      <div class="tree-content" ref="treeContentRef">
         <a-directory-tree ref="treeRef" v-model:expandedKeys="state.expandedKeys" v-model:selectedKeys="selectedKeys" :tree-data="treeData" :field-names="{ title: 'name', key: 'path', children: 'children' }" :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' }" />
@@ -62,6 +63,16 @@
           </template>
         </a-directory-tree>
       </div>
+      <template #overlay>
+        <a-menu @click="handleBackgroundMenuClick">
+          <a-menu-item key="newFile">新建文件</a-menu-item>
+          <a-menu-item key="newFolder">新建文件夹</a-menu-item>
+          <a-menu-divider />
+          <a-menu-item key="refresh">刷新</a-menu-item>
+          <a-menu-item key="openInExplorer">在资源管理器打开</a-menu-item>
+        </a-menu>
+      </template>
+    </a-dropdown>
 
     <!-- 重命名/新建弹窗 -->
     <a-modal v-model:open="modalVisible" :title="modalTitle" @ok="handleModalOk">
@@ -362,6 +373,26 @@ const handleMenuClick = async ({ key }, node) => {
   }
 };
 
+const handleBackgroundMenuClick = ({ key }) => {
+  if (key === 'refresh') {
+    handleRefresh();
+    return;
+  }
+
+  // 构建根目录的虚拟节点
+  const separator = window.utools.isWindows() ? "\\" : "/";
+  // 注意：如果是根驱动器（如 C:\），pop() 可能为空字符串，但 state.rootPath 是完整的
+  const rootName = state.rootPath.split(separator).pop() || state.rootPath;
+  
+  const rootNode = {
+    name: rootName,
+    path: state.rootPath,
+    type: "directory"
+  };
+
+  handleMenuClick({ key }, rootNode);
+};
+
 const handleModalOk = async () => {
   if (!modalInputValue.value) {
     message.warning("请输入内容");
@@ -493,10 +524,8 @@ const handleModalOk = async () => {
 }
 
 :deep(.ant-dropdown-trigger) {
-  display: flex;
   flex: 1;
   min-width: 0;
-  align-items: center;
 }
 
 :deep(.ant-tree-node-content-wrapper:hover) {