Add layout system and file selection logic

Introduce a new layout system for managing main window content and tabs. Integrate file selection and drag-and-drop functionality for adding files to the conversion list, with automatic tab switching to "Added Files". Refactor existing components to support these features.

internal/controller/convertor.go

@@ -1,15 +1,21 @@
 package controller
 
 import (
+	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/internal/ffmpeg"
 	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/internal/ffmpeg/download/service"
 	"git.kor-elf.net/kor-elf/gui-for-ffmpeg/internal/gui/view"
 )
 
 func (c *controller) convertor() {
-	content := view.Convertor()
+	content := view.Convertor(c.window, c.addFileForConversion)
 	c.window.SetContent(content)
 }
 
+func (c *controller) addFileForConversion(file ffmpeg.File) {
+	c.app.GetItemsToConvert().Add(&file)
+	c.window.GetLayout().GetRContainer().SelectAddedFilesTab()
+}
+
 func (c *controller) settingConvertor(isAllowCancellation bool) {
 	ffmpegPath := c.app.GetFFmpegService().GetFFmpegPath()
 	ffprobePath := c.app.GetFFmpegService().GetFFprobePath()

internal/controller/main.go

@@ -22,8 +22,13 @@ func NewController(app application.AppContract) ControllerContract {
 	app.GetQueueService().AddListener(queueLayout)
 
 	return &controller{
-		app:    app,
-		window: window.NewMainWindow(fyneWindow, app.GetProgressBarService(), app.GetItemsToConvert(), queueLayout),
+		app: app,
+		window: window.NewMainWindow(
+			fyneWindow,
+			app.GetProgressBarService(),
+			app.GetItemsToConvert(),
+			queueLayout,
+		),
 	}
 }