fix(posts): post CI Fiber cut-offs in their sequence, not last

b0997f6 moved every cut-off after the parts. Plate.Parts order is the
cut sequence, and the user sets each cut-off's place in it (Set
Sequence), so the post must follow it rather than reorder. Cut-offs
still post as uncompensated open lines with no lead-in.

OpenNest.Tests/CincinnatiCIFiber/CIFiberPostProcessorTests.cs

@@ -223,7 +223,7 @@ public class CIFiberPostProcessorTests
     }
 
     [Fact]
-    public void Post_CutOff_PostsLastWithoutCompensationOrLeadIn()
+    public void Post_CutOff_PostsWithoutCompensationOrLeadIn()
     {
         var nest = MakeSquareWithHoleNest();
         var plate = nest.Plates[0];
@@ -231,17 +231,12 @@ public class CIFiberPostProcessorTests
         // Vertical cut-off at X=20: a bare rapid + line, no lead-in.
         var cutOff = new CutOff(new Vector(20, 0), CutOffAxis.Vertical);
         cutOff.Regenerate(plate, new CutOffSettings());
-        plate.Parts.Insert(0, new Part(cutOff.Drawing, Vector.Zero));
+        plate.Parts.Add(new Part(cutOff.Drawing, Vector.Zero));
 
         var lines = Lines(Post(nest));
 
-        // Cut-off follows the real part despite being first in plate order.
-        var partEnd = lines.IndexOf("( PART END )");
-        var cutOffPart = lines.IndexOf("( Part #2 )");
-        Assert.True(partEnd >= 0 && cutOffPart > partEnd);
-
         var n3 = lines.IndexOf("N3:");
-        Assert.True(n3 > cutOffPart);
+        Assert.True(n3 > lines.IndexOf("( PART:CutOff-V-20.00 )"));
         Assert.Equal("/L \"L0\"", lines[n3 + 1]);
         Assert.Equal("V.E.R3=3", lines[n3 + 2]);
         Assert.StartsWith("G0X20Y", lines[n3 + 3]);
@@ -251,6 +246,34 @@ public class CIFiberPostProcessorTests
         Assert.Equal("/L \"ZHSOFF\"", lines[n3 + 7]);
     }
 
+    [Fact]
+    public void Post_CutOff_FollowsPlateSequence()
+    {
+        // Plate order is the cut sequence: part, cut-off, part. The cut-off is
+        // sequence 2, so it posts second, not after every part.
+        var nest = MakeSquareWithHoleNest();
+        var plate = nest.Plates[0];
+        plate.Parts.Add(new Part(plate.Parts[0].BaseDrawing, new Vector(40, 2)));
+
+        var cutOff = new CutOff(new Vector(20, 0), CutOffAxis.Vertical);
+        cutOff.Regenerate(plate, new CutOffSettings());
+        plate.Parts.Insert(1, new Part(cutOff.Drawing, Vector.Zero));
+
+        var lines = Lines(Post(nest));
+
+        Assert.Equal(
+            new[] { "( PART:square-hole )", "( PART:CutOff-V-20.00 )", "( PART:square-hole )" },
+            lines.Where(l => l.StartsWith("( PART:")).ToArray()
+        );
+
+        // Part number and restart label run in the same order: the first
+        // part's hole and perimeter are N1/N2, so the cut-off is N3.
+        var cutOffBlock = lines.IndexOf("( PART:CutOff-V-20.00 )");
+        Assert.Equal("( Part #2 )", lines[cutOffBlock - 1]);
+        Assert.Equal("V.E.R4=2", lines[cutOffBlock + 1]);
+        Assert.Equal("N3:", lines[cutOffBlock + 2]);
+    }
+
     [Fact]
     public void Post_ValidatesTableSize()
     {

Posts/OpenNest.Posts.CincinnatiCIFiber/CIFiberProgramWriter.cs

@@ -196,14 +196,10 @@ namespace OpenNest.Posts.CincinnatiCIFiber
 
         private int WriteSheet(Plate plate, TextWriter w, int contourNumber)
         {
-            // Cut-offs run last: severing the sheet first would free the
-            // skeleton before the parts are cut (matches the CL post).
-            var ordered = plate
-                .Parts.Where(p => !p.BaseDrawing.IsCutOff)
-                .Concat(plate.Parts.Where(p => p.BaseDrawing.IsCutOff));
-
+            // Plate order is the cut sequence, cut-offs included: the user sets
+            // where each cut-off runs, so the post must not reorder them.
             var partNumber = 0;
-            foreach (var part in ordered)
+            foreach (var part in plate.Parts)
             {
                 partNumber++;
                 contourNumber = WritePart(part, partNumber, w, contourNumber);

docs/cincinnati-ci-fiber-post-output.md

@@ -28,7 +28,9 @@ uses the Cincinnati machine-sample convention, not a generic TF5200 laser API:
   and `%`.
 - Motion endpoints are sheet-absolute XY. Arc `I`/`J` are offsets from the arc
   start, matching the G162 convention; the post does not explicitly emit G162.
-- Sheet cut-offs post after every part on their sheet. Each segment is an open
+- Parts and sheet cut-offs post in the plate's cut sequence (`Plate.Parts`
+  order, as set by Set Sequence or a sequencer). A cut-off is not moved after
+  the parts. Each segment is an open
   line with no lead-in: rapid to its start, `/L "L4"`, `/L "L6"`, the `G1`,
   and `/L "ZHSOFF"`. No `G41`/`G42` is selected, because the line is the beam
   centreline and has no inside or outside. Whether the `L4` macro runs
@@ -85,7 +87,7 @@ validated and saved only when OK is pressed.
 
 [Output-contract tests](../OpenNest.Tests/CincinnatiCIFiber/CIFiberPostProcessorTests.cs)
 cover a square with a hole, coordinate transforms/formatting, lead-in rejection,
-cut-off ordering and output, table bounds, suppression/scribe handling, and
+cut-off sequencing and output, table bounds, suppression/scribe handling, and
 multi-sheet output in both modes. Run:
 
 ```sh