fix: remove dangerous G0 X0 Y0 return-to-home rapids from Cincinnati post

Rapid traversing back to origin over a sheet of freshly cut parts risks
collisions with tipped or warped pieces. Removed from both the sheet
footer and part subprogram endings.

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

OpenNest.Tests/Cincinnati/CincinnatiPostProcessorTests.cs

@@ -258,8 +258,7 @@ public class CincinnatiPostProcessorTests
         Assert.Contains(":200", output);
         Assert.Contains("G84", output);
 
-        // Sub-program ends with G0 X0 Y0 and M99
-        Assert.Contains("G0 X0 Y0", output);
+        // Sub-program ends with M99
         Assert.Contains("M99 (END OF Square)", output);
 
         // G92 restore after M98 call

OpenNest.Tests/Cincinnati/CincinnatiSheetWriterTests.cs

@@ -55,7 +55,6 @@ public class CincinnatiSheetWriterTests
 
         var output = sb.ToString();
         Assert.Contains("M42", output);
-        Assert.Contains("G0 X0 Y0", output);
         Assert.Contains("M50", output);
     }