feat: add Motion.Suppressed property to mark tab-gap codes

Adds Suppressed bool to the Motion base class so LinearMove, ArcMove,
and RapidMove can be flagged for skip during rendering and post-processing
when they fall within a tab gap. Clone() updated on all three subclasses
to preserve the flag. Covered by new MotionSuppressedTests.

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

OpenNest.Core/CNC/ArcMove.cs

@@ -65,7 +65,8 @@ namespace OpenNest.CNC
         {
             return new ArcMove(EndPoint, CenterPoint, Rotation)
             {
-                Layer = Layer
+                Layer = Layer,
+                Suppressed = Suppressed
             };
         }
 

OpenNest.Core/CNC/LinearMove.cs

@@ -31,7 +31,8 @@ namespace OpenNest.CNC
         {
             return new LinearMove(EndPoint)
             {
-                Layer = Layer
+                Layer = Layer,
+                Suppressed = Suppressed
             };
         }
 

OpenNest.Core/CNC/Motion.cs

@@ -12,6 +12,8 @@ namespace OpenNest.CNC
 
         public int Feedrate { get; set; }
 
+        public bool Suppressed { get; set; }
+
         protected Motion()
         {
             Feedrate = CNC.Feedrate.UseDefault;

OpenNest.Core/CNC/RapidMove.cs

@@ -26,7 +26,10 @@ namespace OpenNest.CNC
 
         public override ICode Clone()
         {
-            return new RapidMove(EndPoint);
+            return new RapidMove(EndPoint)
+            {
+                Suppressed = Suppressed
+            };
         }
 
         public override string ToString()

OpenNest.Tests/MotionSuppressedTests.cs

@@ -0,0 +1,45 @@
+using OpenNest.CNC;
+using OpenNest.Geometry;
+
+namespace OpenNest.Tests;
+
+public class MotionSuppressedTests
+{
+    [Fact]
+    public void LinearMove_Suppressed_DefaultsFalse()
+    {
+        var move = new LinearMove(new Vector(1, 2));
+        Assert.False(move.Suppressed);
+    }
+
+    [Fact]
+    public void ArcMove_Suppressed_DefaultsFalse()
+    {
+        var move = new ArcMove(new Vector(1, 2), new Vector(0, 0));
+        Assert.False(move.Suppressed);
+    }
+
+    [Fact]
+    public void RapidMove_Suppressed_DefaultsFalse()
+    {
+        var move = new RapidMove(new Vector(1, 2));
+        Assert.False(move.Suppressed);
+    }
+
+    [Fact]
+    public void Suppressed_CanBeSet()
+    {
+        var move = new LinearMove(new Vector(1, 2));
+        move.Suppressed = true;
+        Assert.True(move.Suppressed);
+    }
+
+    [Fact]
+    public void Clone_PreservesSuppressed()
+    {
+        var move = new LinearMove(new Vector(1, 2));
+        move.Suppressed = true;
+        var clone = (LinearMove)move.Clone();
+        Assert.True(clone.Suppressed);
+    }
+}