feat: placeholder for touch screen editors

GSS2/TouchNumericUpDown.cs

@@ -0,0 +1,22 @@
+using Avalonia;
+using Avalonia.Controls;
+using Avalonia.Input;
+
+namespace GSS2;
+
+public class TouchNumericUpDown : NumericUpDown
+{
+    protected override Type StyleKeyOverride => typeof(NumericUpDown);
+
+    public TouchNumericUpDown()
+    : base()
+    {
+        AddHandler(PointerPressedEvent, OnPointerPressed, handledEventsToo: true);
+    }
+
+    private void OnPointerPressed(object? sender, PointerPressedEventArgs ea)
+    {
+        Console.WriteLine($"TODO: process TouchNumericUpDown.PointerPressed event");
+
+    }
+}