Add directory selection for saving converted files

Introduce logic and UI for selecting and persisting a directory to save converted files. Extend existing components with directory selection buttons, message updates, and storage preferences.

internal/controller/convertor.go

@@ -7,7 +7,12 @@ import (
 )
 
 func (c *controller) convertor() {
-	content := view.Convertor(c.window, c.addFileForConversion)
+	content := view.Convertor(
+		c.window,
+		c.addFileForConversion,
+		c.app.GetSetting().GetDirectoryForSaving(),
+		c.setDirectoryForSaving,
+	)
 	c.window.SetContent(content)
 }
 
@@ -16,6 +21,10 @@ func (c *controller) addFileForConversion(file ffmpeg.File) {
 	c.window.GetLayout().GetRContainer().SelectAddedFilesTab()
 }
 
+func (c *controller) setDirectoryForSaving(path string) {
+	c.app.GetSetting().SetDirectoryForSaving(path)
+}
+
 func (c *controller) settingConvertor(isAllowCancellation bool) {
 	ffmpegPath := c.app.GetFFmpegService().GetFFmpegPath()
 	ffprobePath := c.app.GetFFmpegService().GetFFprobePath()