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/text.go

@@ -0,0 +1,21 @@
+package utils
+
+import (
+	"fyne.io/fyne/v2"
+	"fyne.io/fyne/v2/canvas"
+	"image/color"
+)
+
+func SetStringErrorStyle(text *canvas.Text) {
+	fyne.Do(func() {
+		text.Color = color.RGBA{R: 255, G: 0, B: 0, A: 255}
+		text.Refresh()
+	})
+}
+
+func SetStringSuccessStyle(text *canvas.Text) {
+	fyne.Do(func() {
+		text.Color = color.RGBA{R: 49, G: 127, B: 114, A: 255}
+		text.Refresh()
+	})
+}