feat: add pierce point visualization and rename shape dimensions to Length/Width

Add toggleable pierce point drawing to PlateView that shows small red
filled circles at each rapid move endpoint (where cutting begins). Wire
through View menu, EditNestForm toggle, and MainForm handler.

Also rename RectangleShape/RoundedRectangleShape Width/Height to
Length/Width for consistency with CNC conventions, update MCP tools and
tests accordingly. Fix SplitDrawingForm designer layout ordering and
EntityView bend line selection styling.

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

OpenNest/Controls/PlateView.cs

@@ -131,6 +131,8 @@ namespace OpenNest.Controls
 
         public bool DrawRapid { get; set; }
 
+        public bool DrawPiercePoints { get; set; }
+
         public bool DrawBounds { get; set; }
 
         public bool DrawOffset { get; set; }
@@ -617,6 +619,9 @@ namespace OpenNest.Controls
 
             if (DrawRapid)
                 DrawRapids(g);
+
+            if (DrawPiercePoints)
+                DrawAllPiercePoints(g);
         }
 
         private void DrawBendLines(Graphics g, Part part)
@@ -813,6 +818,54 @@ namespace OpenNest.Controls
             }
         }
 
+        private void DrawAllPiercePoints(Graphics g)
+        {
+            using var brush = new SolidBrush(Color.Red);
+            using var pen = new Pen(Color.DarkRed, 1f);
+
+            for (var i = 0; i < Plate.Parts.Count; ++i)
+            {
+                var part = Plate.Parts[i];
+                var pgm = part.Program;
+                var pos = part.Location;
+                DrawProgramPiercePoints(g, pgm, ref pos, brush, pen);
+            }
+        }
+
+        private void DrawProgramPiercePoints(Graphics g, Program pgm, ref Vector pos, Brush brush, Pen pen)
+        {
+            for (var i = 0; i < pgm.Length; ++i)
+            {
+                var code = pgm[i];
+
+                if (code.Type == CodeType.SubProgramCall)
+                {
+                    var subpgm = (SubProgramCall)code;
+                    if (subpgm.Program != null)
+                        DrawProgramPiercePoints(g, subpgm.Program, ref pos, brush, pen);
+                }
+                else
+                {
+                    var motion = code as Motion;
+                    if (motion == null) continue;
+
+                    var endpt = pgm.Mode == Mode.Incremental
+                        ? motion.EndPoint + pos
+                        : motion.EndPoint;
+
+                    if (code.Type == CodeType.RapidMove)
+                    {
+                        var pt = PointWorldToGraph(endpt);
+                        var radius = 2f;
+                        g.FillEllipse(brush, pt.X - radius, pt.Y - radius, radius * 2, radius * 2);
+                        g.DrawEllipse(pen, pt.X - radius, pt.Y - radius, radius * 2, radius * 2);
+                    }
+
+                    pos = endpt;
+                }
+            }
+        }
+
         private void DrawLine(Graphics g, Vector pt1, Vector pt2, Pen pen)
         {
             var point1 = PointWorldToGraph(pt1);