feat: add Delete key to remove source parts during ActionClone

Enables a "move" workflow: clone parts to a new position, then
press Delete to remove the originals. Previously Delete just
cancelled the clone action.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

OpenNest/Actions/ActionClone.cs

@@ -12,6 +12,7 @@ namespace OpenNest.Actions
     public class ActionClone : Action
     {
         private readonly List<LayoutPart> parts;
+        private readonly List<Part> sourceParts;
 
         private double lastScale;
 
@@ -28,6 +29,7 @@ namespace OpenNest.Actions
             plateView.MouseDown += plateView_MouseDown;
             plateView.Paint += plateView_Paint;
 
+            sourceParts = partsToClone;
             parts = new List<LayoutPart>();
             lastScale = double.NaN;
 
@@ -61,6 +63,16 @@ namespace OpenNest.Actions
                     Apply();
                     break;
 
+                case Keys.Delete:
+                    foreach (var part in sourceParts)
+                        plateView.Plate.Parts.Remove(part);
+
+                    if (plateView.Plate.CutOffs.Count > 0)
+                        plateView.Plate.RegenerateCutOffs(plateView.CutOffSettings);
+
+                    plateView.Invalidate();
+                    break;
+
                 case Keys.F:
                     if ((Control.ModifierKeys & Keys.Control) == Keys.Control)
                         Fill();

OpenNest/Controls/PlateView.cs

@@ -386,11 +386,7 @@ namespace OpenNest.Controls
             switch (e.KeyCode)
             {
                 case Keys.Delete:
-                    if (currentAction is ActionClone)
+                    if (selectedCutOff != null)
-                    {
-                        SetAction(typeof(ActionSelect));
-                    }
-                    else if (selectedCutOff != null)
                     {
                         Plate.CutOffs.Remove(selectedCutOff);
                         selectedCutOff = null;
@@ -853,6 +849,7 @@ namespace OpenNest.Controls
             Invalidate();
         }
 
+
         private void redrawTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
         {
             Invalidate();