void addNewTab(string title, string icon, ContentPage page, bool createNewTabBar = false)
{
    var shell = Application.Current.MainPage as AppShell;
    if (shell == null) return;

    if (createNewTabBar || shell.Items.Count == 0)
    {
        // Создаем новый TabBar с одной вкладкой
        shell.Items.Clear();
        var tabBars = new TabBar();
        shell.Items.Add(tabBars);
    }

    if (shell.Items[0] is TabBar tabBar)
    {
        var newTab = new Tab
        {
            Title = title,
            Icon = icon,
            Items = { new ShellContent { ContentTemplate = new DataTemplate(() => page) } }
        };
        tabBar.Items.Add(newTab);
    }
}