Introduce progress bar updates and queue processing logic

Implemented progress bar integration with `ProgressBarContract` for real-time conversion tracking and status updates. Added queue management functionality to process files sequentially with error and completion handling. Extended `ConvertorContract` and `FFmpegContract` to support tracking of running processes and conversion progress.

main.go

@@ -20,9 +20,9 @@ func main() {
 	}
 	app.SetMetadata(appMetadata)
 	fyneApp := app.New()
-	progressBarService := convertor.NewProgressBar()
 	appSetting := setting.NewSetting(fyneApp)
 	ffmpegService := ffmpeg.NewUtilities(appSetting)
+	progressBarService := convertor.NewProgressBar(ffmpegService)
 	convertorService := convertor.NewConvertor(ffmpegService)
 	itemsToConvert := convertor.NewItemsToConvert(ffmpegService)
 	queue := convertor.NewQueueList()
@@ -37,5 +37,9 @@ func main() {
 	)
 	mainController := controller.NewController(myApp)
 	mainController.Start()
+
+	myApp.RunConvertor()
+	defer myApp.AfterClosing()
+
 	myApp.Run()
 }