feat(cincinnati): emit SubProgramCall features as M98 hole calls

When a feature is a single SubProgramCall, wrap the call with a G52
offset shift, emit M98 P<num>, reset G52, and add M47 between features.
Accepts an optional hole subprogram id map so the post can remap
drawing-local subprogram ids to machine subprogram numbers.

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

OpenNest.Posts.Cincinnati/CincinnatiPartSubprogramWriter.cs

@@ -16,11 +16,16 @@ public sealed class CincinnatiPartSubprogramWriter
 {
     private readonly CincinnatiPostConfig _config;
     private readonly CincinnatiFeatureWriter _featureWriter;
+    private readonly CoordinateFormatter _fmt;
+    private readonly Dictionary<int, int> _holeSubprograms;
 
-    public CincinnatiPartSubprogramWriter(CincinnatiPostConfig config)
+    public CincinnatiPartSubprogramWriter(CincinnatiPostConfig config,
+        Dictionary<int, int> holeSubprograms = null)
     {
         _config = config;
         _featureWriter = new CincinnatiFeatureWriter(config);
+        _fmt = new CoordinateFormatter(config.PostedAccuracy);
+        _holeSubprograms = holeSubprograms;
     }
 
     /// <summary>
@@ -44,6 +49,15 @@ public sealed class CincinnatiPartSubprogramWriter
         for (var i = 0; i < ordered.Count; i++)
         {
             var (codes, isEtch) = ordered[i];
+            var isLastFeature = i == ordered.Count - 1;
+
+            // SubProgramCall features are emitted as M98 hole calls
+            if (codes.Count == 1 && codes[0] is SubProgramCall holeCall)
+            {
+                WriteHoleSubprogramCall(w, holeCall, i, isLastFeature);
+                continue;
+            }
+
             var featureNumber = i == 0
                 ? _config.FeatureLineNumberStart
                 : 1000 + i + 1;
@@ -55,7 +69,7 @@ public sealed class CincinnatiPartSubprogramWriter
                 FeatureNumber = featureNumber,
                 PartName = drawingName,
                 IsFirstFeatureOfPart = false,
-                IsLastFeatureOnSheet = i == ordered.Count - 1,
+                IsLastFeatureOnSheet = isLastFeature,
                 IsSafetyHeadraise = false,
                 IsExteriorFeature = false,
                 IsEtch = isEtch,
@@ -70,6 +84,30 @@ public sealed class CincinnatiPartSubprogramWriter
         w.WriteLine($"M99 (END OF {drawingName})");
     }
 
+    private void WriteHoleSubprogramCall(TextWriter w, SubProgramCall call,
+        int featureIndex, bool isLastFeature)
+    {
+        var postSubNum = _holeSubprograms != null && _holeSubprograms.TryGetValue(call.Id, out var num)
+            ? num : call.Id;
+
+        var featureNumber = featureIndex == 0
+            ? _config.FeatureLineNumberStart
+            : 1000 + featureIndex + 1;
+
+        var sb = new StringBuilder();
+        if (_config.UseLineNumbers)
+            sb.Append($"N{featureNumber} ");
+        sb.Append($"G52 X{_fmt.FormatCoord(call.Offset.X)} Y{_fmt.FormatCoord(call.Offset.Y)}");
+        w.WriteLine(sb.ToString());
+
+        w.WriteLine($"M98 P{postSubNum}");
+
+        w.WriteLine("G52 X0 Y0");
+
+        if (!isLastFeature)
+            w.WriteLine("M47");
+    }
+
     /// <summary>
     /// If the program has no leading rapid, inserts a synthetic rapid at the
     /// last motion endpoint (the contour return point). This ensures the feature