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})
+}

internal/utils/path_separator.go

@@ -0,0 +1,8 @@
+//go:build !windows
+// +build !windows
+
+package utils
+
+func PathSeparator() string {
+	return "/"
+}

internal/utils/path_separator_window.go

@@ -0,0 +1,8 @@
+//go:build windows
+// +build windows
+
+package utils
+
+func PathSeparator() string {
+	return "\\"
+}

internal/utils/prepare_background_command.go

@@ -0,0 +1,12 @@
+//go:build !windows
+// +build !windows
+
+package utils
+
+import (
+	"os/exec"
+)
+
+func PrepareBackgroundCommand(cmd *exec.Cmd) {
+
+}

internal/utils/prepare_background_command_windows.go

@@ -0,0 +1,13 @@
+//go:build windows
+// +build windows
+
+package utils
+
+import (
+	"os/exec"
+	"syscall"
+)
+
+func PrepareBackgroundCommand(cmd *exec.Cmd) {
+	cmd.SysProcAttr = &syscall.SysProcAttr{HideWindow: true}
+}

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()
+	})
+}