refactor(app): 重构应用状态管理和配置常量定义

- 将全局变量 isRun 移动到 App 结构体内部作为实例字段
- 在 config.go 中定义配置键名为常量，提高代码可维护性
- 使用结构体实例字段替代全局变量管理上传状态
- 修改 StartLooking 函数中的上下文取消处理逻辑
- 移除上传程序退出日志的重复记录

app.go

@@ -16,10 +16,9 @@ type App struct {
 	logChan        chan string
 	uploaderCTX    context.Context
 	uploaderCancel context.CancelFunc
+	isRun          bool
 }
 
-var isRun = false
-
 func NewApp() *App {
 	return &App{}
 }
@@ -40,8 +39,8 @@ func (a *App) startup(ctx context.Context) {
 	a.uploaderCTX, a.uploaderCancel = context.WithCancel(a.ctx)
 	if config.APPConfig.IsRunOnStart {
 		time.Sleep(time.Second)
-		isRun = true
 		go uploader.StartLooking(a.uploaderCTX, &a.logChan, config.APPConfig.CheckDir)
+		a.isRun = true
 	}
 }
 
@@ -62,15 +61,18 @@ func (a *App) WriteConfig(key string, value any) {
 }
 
 func (a *App) StartUpload() {
-	if isRun {
+	if a.isRun {
 		return
 	}
 	a.uploaderCTX, a.uploaderCancel = context.WithCancel(a.ctx)
 	go uploader.StartLooking(a.uploaderCTX, &a.logChan, config.APPConfig.CheckDir)
+	a.isRun = true
 }
 
 func (a *App) StopUpload() {
-	if isRun {
+	if a.isRun {
 		a.uploaderCancel()
 	}
+	a.isRun = false
+	uploader.AddLog(&a.logChan, "上传程序已退出")
 }