feat: add CincinnatiPostProcessor implementing IPostProcessor

Orchestrates CincinnatiPreambleWriter and CincinnatiSheetWriter to produce
a complete Cincinnati CNC output file from a Nest; includes 4 integration tests.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

OpenNest.Posts.Cincinnati/CincinnatiPostProcessor.cs

@@ -0,0 +1,77 @@
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Text;
+
+namespace OpenNest.Posts.Cincinnati
+{
+    public sealed class CincinnatiPostProcessor : IPostProcessor
+    {
+        public string Name => "Cincinnati CL-707";
+        public string Author => "OpenNest";
+        public string Description => "Cincinnati CL-707/CL-800/CL-900/CL-940/CLX family";
+
+        public CincinnatiPostConfig Config { get; }
+
+        public CincinnatiPostProcessor(CincinnatiPostConfig config)
+        {
+            Config = config;
+        }
+
+        public void Post(Nest nest, Stream outputStream)
+        {
+            // 1. Create variable manager and register standard variables
+            var vars = CreateVariableManager();
+
+            // 2. Filter to non-empty plates
+            var plates = nest.Plates
+                .Where(p => p.Parts.Count > 0)
+                .ToList();
+
+            // 3. Create writers
+            var preamble = new CincinnatiPreambleWriter(Config);
+            var sheetWriter = new CincinnatiSheetWriter(Config, vars);
+
+            // 4. Build material description from first plate
+            var material = plates.FirstOrDefault()?.Material;
+            var materialDesc = material != null
+                ? $"{material.Name}{(string.IsNullOrEmpty(material.Grade) ? "" : $", {material.Grade}")}"
+                : "";
+
+            // 5. Write to stream
+            using var writer = new StreamWriter(outputStream, Encoding.UTF8, 1024, leaveOpen: true);
+
+            // Main program
+            preamble.WriteMainProgram(writer, nest.Name ?? "NEST", materialDesc, plates.Count);
+
+            // Variable declaration subprogram
+            preamble.WriteVariableDeclaration(writer, vars);
+
+            // Sheet subprograms
+            for (var i = 0; i < plates.Count; i++)
+            {
+                var sheetIndex = i + 1;
+                var subNumber = Config.SheetSubprogramStart + i;
+                sheetWriter.Write(writer, plates[i], nest.Name ?? "NEST", sheetIndex, subNumber);
+            }
+
+            writer.Flush();
+        }
+
+        public void Post(Nest nest, string outputFile)
+        {
+            using var fs = new FileStream(outputFile, FileMode.Create, FileAccess.Write);
+            Post(nest, fs);
+        }
+
+        private ProgramVariableManager CreateVariableManager()
+        {
+            var vars = new ProgramVariableManager();
+            vars.GetOrCreate("ProcessFeedrate", 148);  // Set by G89, no expression
+            vars.GetOrCreate("LeadInFeedrate", 126, $"[#148*{Config.LeadInFeedratePercent}]");
+            vars.GetOrCreate("LeadInArcLine2Feedrate", 127, $"[#148*{Config.LeadInArcLine2FeedratePercent}]");
+            vars.GetOrCreate("CircleFeedrate", 128, Config.CircleFeedrateMultiplier.ToString("0.#"));
+            return vars;
+        }
+    }
+}

OpenNest.Tests/Cincinnati/CincinnatiPostProcessorTests.cs

@@ -0,0 +1,122 @@
+using System.IO;
+using System.Text;
+using OpenNest.CNC;
+using OpenNest.Geometry;
+using OpenNest.Posts.Cincinnati;
+
+namespace OpenNest.Tests.Cincinnati;
+
+public class CincinnatiPostProcessorTests
+{
+    [Fact]
+    public void Post_ProducesOutput_ForSinglePlateNest()
+    {
+        var nest = CreateTestNest();
+        var config = new CincinnatiPostConfig
+        {
+            ConfigurationName = "CL940",
+            DefaultLibraryFile = "MS135N2PANEL.lib",
+            PostedAccuracy = 4
+        };
+        var post = new CincinnatiPostProcessor(config);
+
+        using var ms = new MemoryStream();
+        post.Post(nest, ms);
+
+        var output = Encoding.UTF8.GetString(ms.ToArray());
+
+        // Main program elements
+        Assert.Contains("( NEST TestNest )", output);
+        Assert.Contains("( CONFIGURATION - CL940 )", output);
+        Assert.Contains("G20", output);
+        Assert.Contains("M30 (END OF MAIN)", output);
+
+        // Variable declaration
+        Assert.Contains(":100", output);
+        Assert.Contains("#126=", output);
+
+        // Sheet subprogram
+        Assert.Contains(":101", output);
+        Assert.Contains("( Sheet 1 )", output);
+        Assert.Contains("G84", output);
+        Assert.Contains("M99", output);
+    }
+
+    [Fact]
+    public void Post_ImplementsIPostProcessor()
+    {
+        var post = new CincinnatiPostProcessor(new CincinnatiPostConfig());
+        IPostProcessor pp = post;
+
+        Assert.Equal("Cincinnati CL-707", pp.Name);
+        Assert.Equal("OpenNest", pp.Author);
+    }
+
+    [Fact]
+    public void Post_SkipsEmptyPlates()
+    {
+        var nest = new Nest("TestNest");
+        nest.Plates.Add(new Plate(48, 96)); // empty plate
+        var plate2 = new Plate(48, 96);
+        plate2.Parts.Add(new Part(new Drawing("Part1", CreateSquareProgram())));
+        nest.Plates.Add(plate2);
+
+        var config = new CincinnatiPostConfig { PostedAccuracy = 4 };
+        var post = new CincinnatiPostProcessor(config);
+
+        using var ms = new MemoryStream();
+        post.Post(nest, ms);
+
+        var output = Encoding.UTF8.GetString(ms.ToArray());
+
+        // Should only have one sheet subprogram call in main
+        Assert.Contains("N1M98 P101 (SHEET 1)", output);
+        Assert.DoesNotContain("SHEET 2", output);
+    }
+
+    [Fact]
+    public void Post_ToFile_CreatesFile()
+    {
+        var nest = CreateTestNest();
+        var config = new CincinnatiPostConfig { PostedAccuracy = 4 };
+        var post = new CincinnatiPostProcessor(config);
+        var tempFile = Path.GetTempFileName() + ".CNC";
+
+        try
+        {
+            post.Post(nest, tempFile);
+            Assert.True(File.Exists(tempFile));
+            var content = File.ReadAllText(tempFile);
+            Assert.Contains("M30", content);
+        }
+        finally
+        {
+            if (File.Exists(tempFile))
+                File.Delete(tempFile);
+        }
+    }
+
+    private static Nest CreateTestNest()
+    {
+        var nest = new Nest("TestNest");
+        var drawing = new Drawing("Square", CreateSquareProgram());
+        nest.Drawings.Add(drawing);
+
+        var plate = new Plate(48.0, 96.0);
+        plate.Parts.Add(new Part(drawing, new Vector(10, 10)));
+        nest.Plates.Add(plate);
+
+        return nest;
+    }
+
+    private static Program CreateSquareProgram()
+    {
+        var pgm = new Program();
+        pgm.Codes.Add(new RapidMove(0, 0));
+        pgm.Codes.Add(new LinearMove(2, 0));
+        pgm.Codes.Add(new LinearMove(2, 2));
+        pgm.Codes.Add(new LinearMove(0, 2));
+        pgm.Codes.Add(new LinearMove(0, 0));
+        return pgm;
+    }
+}