Add FFmpeg utilities configuration UI and automated downloading

Introduce a new UI for configuring FFmpeg, FFprobe, and FFplay paths with file selection and error handling. Add platform-specific logic for downloading and extracting FFmpeg binaries directly within the application, improving user experience.

internal/ffmpeg/download/gui/download_windows.go

@@ -0,0 +1,59 @@
+//go:build windows
+// +build windows
+
+package gui
+
+import (
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"fyne.io/fyne/v2/container"
+	"fyne.io/fyne/v2/lang"
+	"fyne.io/fyne/v2/widget"
+	"golang.org/x/image/colornames"
+	"image/color"
+)
+
+func DownloadFFmpeg(donwloadFFmpeg func(progressBar *widget.ProgressBar, progressMessage *canvas.Text) error) fyne.CanvasObject {
+	errorDownloadFFmpegMessage := canvas.NewText("", color.RGBA{R: 255, G: 0, B: 0, A: 255})
+	errorDownloadFFmpegMessage.TextSize = 16
+	errorDownloadFFmpegMessage.TextStyle = fyne.TextStyle{Bold: true}
+
+	progressDownloadFFmpegMessage := canvas.NewText("", color.RGBA{R: 49, G: 127, B: 114, A: 255})
+	progressDownloadFFmpegMessage.TextSize = 16
+	progressDownloadFFmpegMessage.TextStyle = fyne.TextStyle{Bold: true}
+
+	progressBar := widget.NewProgressBar()
+
+	var buttonDownloadFFmpeg *widget.Button
+
+	buttonDownloadFFmpeg = widget.NewButton(lang.L("download"), func() {
+
+		go func() {
+			fyne.Do(func() {
+				buttonDownloadFFmpeg.Disable()
+			})
+			err := donwloadFFmpeg(progressBar, progressDownloadFFmpegMessage)
+			if err != nil {
+				errorDownloadFFmpegMessage.Text = err.Error()
+			}
+			fyne.Do(func() {
+				buttonDownloadFFmpeg.Enable()
+			})
+		}()
+	})
+
+	downloadFFmpegFromSiteMessage := lang.L("downloadFFmpegFromSite")
+
+	return container.NewVBox(
+		canvas.NewLine(colornames.Darkgreen),
+		widget.NewCard(lang.L("buttonDownloadFFmpeg"), "", container.NewVBox(
+			widget.NewRichTextFromMarkdown(
+				downloadFFmpegFromSiteMessage+" [https://github.com/BtbN/FFmpeg-Builds/releases](https://github.com/BtbN/FFmpeg-Builds/releases)",
+			),
+			buttonDownloadFFmpeg,
+			container.NewHScroll(errorDownloadFFmpegMessage),
+			progressDownloadFFmpegMessage,
+			progressBar,
+		)),
+	)
+}