feat(core,io): persist nest status and made-by in nest files

Add NestStatus (Quote/ToBeCut/HasBeenCut) plus MadeBy on Nest, written as
additive camelCase nest.json fields with PascalCase enum strings matching
the units convention. Legacy files and unknown status values fall back to
Quote. The nest info dialog gains a Status dropdown and Made By box.

OpenNest.Tests/IO/NestStatusSerializationTests.cs

@@ -0,0 +1,173 @@
+using System.IO;
+using System.IO.Compression;
+using System.Linq;
+using System.Text;
+using System.Text.Json;
+using OpenNest.Geometry;
+using OpenNest.IO;
+
+namespace OpenNest.Tests.IO;
+
+public class NestStatusSerializationTests
+{
+    [Fact]
+    public void RoundTrip_StatusAndMadeBy_Preserved()
+    {
+        var nest = CreateMinimalNest();
+        nest.Status = NestStatus.ToBeCut;
+        nest.MadeBy = "AJ";
+
+        var loaded = RoundTrip(nest);
+
+        Assert.Equal(NestStatus.ToBeCut, loaded.Status);
+        Assert.Equal("AJ", loaded.MadeBy);
+    }
+
+    [Fact]
+    public void RoundTrip_DefaultStatus_IsQuote()
+    {
+        var loaded = RoundTrip(CreateMinimalNest());
+
+        Assert.Equal(NestStatus.Quote, loaded.Status);
+        Assert.Equal("", loaded.MadeBy);
+    }
+
+    [Fact]
+    public void RoundTrip_HasBeenCut_Preserved()
+    {
+        var nest = CreateMinimalNest();
+        nest.Status = NestStatus.HasBeenCut;
+
+        var loaded = RoundTrip(nest);
+
+        Assert.Equal(NestStatus.HasBeenCut, loaded.Status);
+    }
+
+    [Fact]
+    public void Status_SerializedAsEnumString()
+    {
+        var nest = CreateMinimalNest();
+        nest.Status = NestStatus.ToBeCut;
+        nest.MadeBy = "Rex";
+
+        using var ms = new MemoryStream();
+        new NestWriter(nest).Write(ms);
+        var dtoJson = ReadNestJson(ms);
+        using var doc = JsonDocument.Parse(dtoJson);
+
+        // Enum strings follow the existing units convention (PascalCase).
+        Assert.Equal("ToBeCut", doc.RootElement.GetProperty("status").GetString());
+        Assert.Equal("Rex", doc.RootElement.GetProperty("madeBy").GetString());
+    }
+
+    [Fact]
+    public void LegacyFile_WithoutStatusFields_LoadsDefaults()
+    {
+        var nest = CreateMinimalNest();
+        using var ms = new MemoryStream();
+        new NestWriter(nest).Write(ms);
+
+        // Rebuild the archive with the additive fields stripped from nest.json.
+        var rebuilt = StripFields(ms, "status", "madeBy");
+
+        var loaded = new NestReader(rebuilt).Read();
+
+        Assert.Equal(NestStatus.Quote, loaded.Status);
+        Assert.Equal("", loaded.MadeBy);
+    }
+
+    [Fact]
+    public void File_WithUnknownStatusValue_LoadsQuote()
+    {
+        var nest = CreateMinimalNest();
+        using var ms = new MemoryStream();
+        new NestWriter(nest).Write(ms);
+        var rebuilt = ReplaceField(ms, "status", "Banana");
+
+        var loaded = new NestReader(rebuilt).Read();
+
+        Assert.Equal(NestStatus.Quote, loaded.Status);
+    }
+
+    private static Nest CreateMinimalNest()
+    {
+        var program = new OpenNest.CNC.Program();
+        program.Codes.Add(new OpenNest.CNC.LinearMove(new Vector(10, 0)));
+        var drawing = new Drawing("Part", program);
+        var nest = new Nest { Name = "Test" };
+        nest.Drawings.Add(drawing);
+        var plate = new Plate(new Size(100, 100));
+        plate.Parts.Add(new Part(drawing, new Vector(0, 0)));
+        nest.Plates.Add(plate);
+        return nest;
+    }
+
+    private static Nest RoundTrip(Nest nest)
+    {
+        var ms = new MemoryStream();
+        new NestWriter(nest).Write(ms);
+        ms.Position = 0;
+        return new NestReader(ms).Read();
+    }
+
+    private static string ReadNestJson(MemoryStream archive)
+    {
+        archive.Position = 0;
+        using var zip = new ZipArchive(archive, ZipArchiveMode.Read, leaveOpen: true);
+        using var reader = new StreamReader(
+            zip.GetEntry("nest.json").Open(), Encoding.UTF8);
+        return reader.ReadToEnd();
+    }
+
+    private static MemoryStream RewriteNestJson(MemoryStream archive, string json)
+    {
+        var output = new MemoryStream();
+        archive.Position = 0;
+        using (var source = new ZipArchive(archive, ZipArchiveMode.Read, leaveOpen: true))
+        using (var target = new ZipArchive(output, ZipArchiveMode.Create, leaveOpen: true))
+        {
+            foreach (var entry in source.Entries)
+            {
+                var newEntry = target.CreateEntry(entry.FullName);
+                using var sourceStream = entry.Open();
+                using var targetStream = newEntry.Open();
+                if (entry.FullName == "nest.json")
+                {
+                    using var writer = new StreamWriter(targetStream, Encoding.UTF8);
+                    writer.Write(json);
+                }
+                else
+                {
+                    sourceStream.CopyTo(targetStream);
+                }
+            }
+        }
+        output.Position = 0;
+        return output;
+    }
+
+    private static MemoryStream StripFields(MemoryStream archive, params string[] fields)
+    {
+        using var doc = JsonDocument.Parse(ReadNestJson(archive));
+        var options = new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+        };
+        var root = doc.RootElement.Deserialize<Dictionary<string, JsonElement>>(options);
+        foreach (var field in fields)
+            root.Remove(field);
+        return RewriteNestJson(archive, JsonSerializer.Serialize(root, options));
+    }
+
+    private static MemoryStream ReplaceField(MemoryStream archive, string field, string value)
+    {
+        using var doc = JsonDocument.Parse(ReadNestJson(archive));
+        var options = new JsonSerializerOptions
+        {
+            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
+        };
+        var root = doc.RootElement.Deserialize<Dictionary<string, JsonElement>>(options);
+        root[field] = JsonSerializer.Deserialize<JsonElement>($"\"{value}\"");
+        return RewriteNestJson(archive, JsonSerializer.Serialize(root, options));
+    }
+}