refactor: remove default_install_dir, Update uses built-in default path

backend/internal/model/models.go

@@ -229,7 +229,6 @@ type Version struct {
 	EntryFile           string         `gorm:"size:255" json:"entry_file"`
 	EntryFiles          string         `gorm:"type:text" json:"entry_files"`                       // JSON数组，可启动的入口文件
 	DesktopShortcutFiles string        `gorm:"type:text" json:"desktop_shortcut_files"`            // JSON数组，需要创建桌面快捷方式的文件
-	DefaultInstallDir   string         `gorm:"size:500" json:"default_install_dir"`                // 默认安装目录
 	UpdateStrategy      string         `gorm:"size:20;default:optional" json:"update_strategy"`
 	UpdateType          string         `gorm:"size:20;default:full" json:"update_type"`
 	UpdateMethod        string         `gorm:"size:20;default:auto" json:"update_method"`

backend/internal/router/admin/versions.go

@@ -256,7 +256,6 @@ func handleGetVersionByID(c *gin.Context) {
 		"entry_file":              version.EntryFile,
 		"entry_files":             version.EntryFiles,
 		"desktop_shortcut_files":  version.DesktopShortcutFiles,
-		"default_install_dir":     version.DefaultInstallDir,
 		"full_package_path":       version.FullPackagePath,
 		"full_package_size":       version.FullPackageSize,
 		"full_package_hash":       version.FullPackageHash,
@@ -275,7 +274,6 @@ type CreateVersionRequest struct {
 	EntryFile             string             `json:"entry_file"`
 	EntryFiles            string             `json:"entry_files"`
 	DesktopShortcutFiles  string             `json:"desktop_shortcut_files"`
-	DefaultInstallDir     string             `json:"default_install_dir"`
 	UpdateStrategy        string             `json:"update_strategy"`
 	UpdateType            string             `json:"update_type"`
 	UpdateMethod          string             `json:"update_method"`
@@ -330,7 +328,6 @@ func handleCreateVersionGlobal(c *gin.Context) {
 		EntryFile:             req.EntryFile,
 		EntryFiles:            req.EntryFiles,
 		DesktopShortcutFiles:  req.DesktopShortcutFiles,
-		DefaultInstallDir:     req.DefaultInstallDir,
 		UpdateStrategy:        req.UpdateStrategy,
 		UpdateType:            req.UpdateType,
 		UpdateMethod:          req.UpdateMethod,
@@ -475,7 +472,6 @@ type UpdateVersionRequest struct {
 	EntryFile             string             `json:"entry_file"`
 	EntryFiles            string             `json:"entry_files"`
 	DesktopShortcutFiles  string             `json:"desktop_shortcut_files"`
-	DefaultInstallDir     string             `json:"default_install_dir"`
 	UpdateStrategy        string             `json:"update_strategy"`
 	UpdateType            string             `json:"update_type"`
 	UpdateMethod          string             `json:"update_method"`
@@ -543,7 +539,6 @@ func handleUpdateVersionGlobal(c *gin.Context) {
 	updates["entry_file"] = req.EntryFile
 	updates["entry_files"] = req.EntryFiles
 	updates["desktop_shortcut_files"] = req.DesktopShortcutFiles
-	updates["default_install_dir"] = req.DefaultInstallDir
 	if req.UpdateStrategy != "" {
 		updates["update_strategy"] = req.UpdateStrategy
 	}

backend/internal/router/app/info.go

@@ -122,8 +122,7 @@ func handleAppCheckUpdate(c *gin.Context) {
 			"entry_file":             latestVersion.EntryFile,
 			"entry_files":            latestVersion.EntryFiles,
 			"desktop_shortcut_files": latestVersion.DesktopShortcutFiles,
-			"default_install_dir":    latestVersion.DefaultInstallDir,
-			"update_notes":           latestVersion.Description,
+			"update_notes":            latestVersion.Description,
 			"update_strategy":        latestVersion.UpdateStrategy,
 			"update_type":            latestVersion.UpdateType,
 			"update_method":          latestVersion.UpdateMethod,