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/utils/dialog.go

@@ -0,0 +1,11 @@
+package utils
+
+import (
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/dialog"
+)
+
+func FileDialogResize(fileDialog *dialog.FileDialog, w fyne.Window) {
+	contentSize := w.Content().Size()
+	fileDialog.Resize(fyne.Size{Width: contentSize.Width - 50, Height: contentSize.Height - 50})
+}