Dialogs

ViewModels depend on IDialogs and INotifier, never on Page.DisplayAlert. UseDialogs() registers MauiDialogs and MauiNotifier. Both hop to IMainThread. MauiToastPresenter draws on Window.AddOverlay and never wraps or replaces Page.Content.

var ok = await dialogs.ConfirmAsync(
    "Delete product",
    "This cannot be undone.",
    accept: "Delete",
    cancel: "Cancel",
    cancellationToken);

if (ok)
{
    await catalog.DeleteAsync(id, cancellationToken);
    await notifier.ToastAsync("Deleted", cancellationToken: cancellationToken);
}

NullDialogs implements both interfaces as no-ops. FakeDialogs records alerts and lets the test set ConfirmResult. There is no FakeNotifier type — FakeDialogs is INotifier. Inject IToastPresenter to record toasts without a window.