fix: 用户编辑弹窗修复 — footer 简化 + 删除后关闭弹窗

- footer 用 span 替代 flex div (避免 element-plus 兼容问题)
- 删除成功后自动关闭弹窗

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/views/desktop/UserManage.vue

@@ -65,6 +65,7 @@ async function handleDelete(row: any) {
     await ElMessageBox.confirm(`确定删除「${row.name}」？此操作不可恢复。`, '确认删除', { type: 'warning', confirmButtonText: '删除', cancelButtonText: '取消' })
     await api.delete(`/users/${row.id}`)
     ElMessage.success(`已删除「${row.name}」`)
+    editDialogVisible.value = false
     await loadUsers()
   } catch (e: any) { if (e !== 'cancel') ElMessage.error('删除失败: ' + (e.response?.data?.detail || e.message)) }
 }
@@ -127,13 +128,11 @@ async function handleDelete(row: any) {
         </el-form>
       </template>
       <template #footer>
-        <div style="display:flex;justify-content:space-between;width:100%">
-          <el-button v-if="auth.isDirector" type="danger" @click="handleDelete(editUser)">删除用户</el-button>
-          <div>
-            <el-button @click="editDialogVisible = false">取消</el-button>
-            <el-button type="primary" @click="handleSave">保存</el-button>
-          </div>
-        </div>
+        <span>
+          <el-button v-if="auth.isDirector" type="danger" @click="handleDelete(editUser)" style="float:left">删除用户</el-button>
+          <el-button @click="editDialogVisible = false">取消</el-button>
+          <el-button type="primary" @click="handleSave">保存</el-button>
+        </span>
       </template>
     </el-dialog>
   </div>