remove MicrotabLeadOut — redundant with normal tabs

MicrotabLeadOut was an unimplemented stub (Generate returned empty list)
that duplicated tab functionality. Existing saved configs with "Microtab"
selected will gracefully fall back to NoLeadOut.

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

OpenNest.Core/CNC/CuttingStrategy/LeadOuts/MicrotabLeadOut.cs

@@ -1,16 +0,0 @@
-using OpenNest.Geometry;
-using System.Collections.Generic;
-
-namespace OpenNest.CNC.CuttingStrategy
-{
-    public class MicrotabLeadOut : LeadOut
-    {
-        public double GapSize { get; set; } = 0.03;
-
-        public override List<ICode> Generate(Vector contourEndPoint, double contourNormalAngle,
-            RotationType winding = RotationType.CW)
-        {
-            return new List<ICode>();
-        }
-    }
-}

OpenNest/Controls/CuttingPanel.cs

@@ -11,7 +11,7 @@ namespace OpenNest.Controls
             { "None", "Line", "Arc", "Line + Arc", "Clean Hole", "Line + Line" };
 
         private static readonly string[] LeadOutTypes =
-            { "None", "Line", "Arc", "Microtab" };
+            { "None", "Line", "Arc" };
 
         private readonly TabControl tabControl;
         private readonly ComboBox cboExternalLeadIn, cboExternalLeadOut;
@@ -424,9 +424,6 @@ namespace OpenNest.Controls
                 case 2:
                     AddNumericField(panel, "Radius:", 0.25, ref y, "Radius");
                     break;
-                case 3:
-                    AddNumericField(panel, "Gap Size:", 0.06, ref y, "GapSize");
-                    break;
             }
         }
 
@@ -513,10 +510,6 @@ namespace OpenNest.Controls
                     combo.SelectedIndex = 2;
                     SetParam(panel, "Radius", arc.Radius);
                     break;
-                case MicrotabLeadOut microtab:
-                    combo.SelectedIndex = 3;
-                    SetParam(panel, "GapSize", microtab.GapSize);
-                    break;
                 default:
                     combo.SelectedIndex = 0;
                     break;
@@ -572,10 +565,6 @@ namespace OpenNest.Controls
                 {
                     Radius = GetParam(panel, "Radius", 0.25)
                 },
-                3 => new MicrotabLeadOut
-                {
-                    GapSize = GetParam(panel, "GapSize", 0.06)
-                },
                 _ => new NoLeadOut()
             };
         }

OpenNest/Forms/CuttingParametersSerializer.cs

@@ -85,7 +85,6 @@ namespace OpenNest.Forms
             {
                 LineLeadOut line => new LeadOutDto { Type = "Line", Length = line.Length, ApproachAngle = line.ApproachAngle },
                 ArcLeadOut arc => new LeadOutDto { Type = "Arc", Radius = arc.Radius },
-                MicrotabLeadOut mt => new LeadOutDto { Type = "Microtab", GapSize = mt.GapSize },
                 _ => new LeadOutDto { Type = "None" }
             };
         }
@@ -97,7 +96,6 @@ namespace OpenNest.Forms
             {
                 "Line" => new LineLeadOut { Length = dto.Length, ApproachAngle = dto.ApproachAngle },
                 "Arc" => new ArcLeadOut { Radius = dto.Radius },
-                "Microtab" => new MicrotabLeadOut { GapSize = dto.GapSize },
                 _ => new NoLeadOut()
             };
         }