优化：代码质量提升，修复重复逻辑和语法高亮支持

- 简化计算属性，删除重复代码
- 优化文件扩展名获取逻辑
- 新增文件工具函数库 fileHelpers.js
- 增强 CodeEditor 语法高亮（支持 30+ 语言）
- 修复 Office 文档文件服务器访问权限
- 添加特殊文件名支持（Dockerfile、Makefile 等）

internal/service/update.go

@@ -12,6 +12,8 @@ import (
 	"runtime"
 	"strings"
 	"time"
+
+	"u-desk/internal/common"
 )
 
 // ==================== 类型定义 ====================
@@ -409,18 +411,13 @@ func BackupApplication() (string, error) {
 		return "", err
 	}
 
-	homeDir, err := os.UserHomeDir()
-	if err != nil {
-		return "", fmt.Errorf("获取用户目录失败: %v", err)
-	}
-
-	backupDir := filepath.Join(homeDir, ".go-desk", "backups")
+	backupDir := filepath.Join(common.GetUserDataDir(), "backups")
 	if err := os.MkdirAll(backupDir, 0755); err != nil {
 		return "", fmt.Errorf("创建备份目录失败: %v", err)
 	}
 
 	timestamp := time.Now().Format("20060102-150405")
-	backupFileName := fmt.Sprintf("go-desk-backup-%s%s", timestamp, filepath.Ext(execPath))
+	backupFileName := fmt.Sprintf("u-desk-backup-%s%s", timestamp, filepath.Ext(execPath))
 	backupPath := filepath.Join(backupDir, backupFileName)
 
 	if err := copyFile(execPath, backupPath); err != nil {