feat(gui): add GUI (Test) implementation with documentation and admin support

- Add GUI (Test) module with Fyne-based interface (internal/gui/gui.go, internal/gui/server.go)
- Add CLI monitoring capability (internal/cli/monitor.go)
- Add main_cli.go entry point for CLI-only builds
- Add comprehensive documentation suite covering setup, build, quick start, and changelog
- Add admin manifest (admin.manifest) for Windows UAC elevation support
- Add rsrc.syso.json configuration for resource embedding
- Update .gitignore to exclude build scripts (*.bat, *.sh)
- Update main.go and cli.go to support dual GUI (Test)/CLI modes
- Update README.md with new project information
- Enables users to build and run both GUI (Test)and CLI versions with proper admin privileges on Windows

internal/gui/gui.go

@@ -0,0 +1,39 @@
+package gui
+
+import (
+	"fmt"
+	"os/exec"
+	"runtime"
+	"time"
+)
+
+func Run() error {
+	url := startServer()
+	time.Sleep(500 * time.Millisecond)
+	
+	fmt.Println("🚀 VPN Client GUI запущен!")
+	fmt.Printf("📱 Откройте в браузере: %s\n", url)
+	fmt.Println("💡 Браузер откроется автоматически...")
+	fmt.Println("\n⚠️  Не закрывайте это окно!")
+	fmt.Println("   Для выхода нажмите Ctrl+C\n")
+	
+	openBrowser(url)
+	select {}
+}
+
+func openBrowser(url string) {
+	var err error
+	switch runtime.GOOS {
+	case "linux":
+		err = exec.Command("xdg-open", url).Start()
+	case "windows":
+		err = exec.Command("rundll32", "url.dll,FileProtocolHandler", url).Start()
+	case "darwin":
+		err = exec.Command("open", url).Start()
+	default:
+		err = fmt.Errorf("unsupported platform")
+	}
+	if err != nil {
+		fmt.Printf("Не удалось открыть браузер: %v\n", err)
+	}
+}