test: cover p-rec-annot line-number list planning

Plant3D2026/P_Rec_Annot/src/PRecAnnot.Core/LineNumberListPlanner.cs

@@ -0,0 +1,19 @@
+using System.Security.Cryptography;
+using System.Text;
+using PRecAnnot.Abstractions;
+
+namespace PRecAnnot.Core;
+
+public static class LineNumberListPlanner
+{
+    public static LineNumberListApplyPreflight Build(AnnotationPoint position, double rotation, IEnumerable<LineNumberApplyPreflight> rows)
+    {
+        var ordered = rows.OrderBy(row => row.MarkerNumber).ToArray();
+        if (ordered.Length == 0) throw new ArgumentException("LINE_NUMBER_LIST_EMPTY", nameof(rows));
+        if (ordered.Any(row => string.IsNullOrWhiteSpace(row.StableId) || string.IsNullOrWhiteSpace(row.Text))) throw new ArgumentException("LINE_NUMBER_LIST_ROW_INVALID", nameof(rows));
+        if (ordered.Select(row => row.MarkerNumber).Distinct().Count() != ordered.Length) throw new ArgumentException("LINE_NUMBER_LIST_DUPLICATE_MARKER_NUMBER", nameof(rows));
+        var key = string.Join("|", ordered.Select(row => $"{row.MarkerNumber}:{row.StableId}"));
+        var digest = Convert.ToHexString(SHA256.HashData(Encoding.UTF8.GetBytes(key))).ToLowerInvariant();
+        return new($"ln-list:{digest}", position, rotation, ordered);
+    }
+}

Plant3D2026/P_Rec_Annot/tests/PRecAnnot.Core.Tests/LineNumberListPlannerTests.cs

@@ -0,0 +1,25 @@
+using PRecAnnot.Abstractions;
+using PRecAnnot.Core;
+
+namespace PRecAnnot.Core.Tests;
+
+public sealed class LineNumberListPlannerTests
+{
+    [Fact]
+    public void ProducesStableOwnershipAndMarkerOrder()
+    {
+        var second = new LineNumberApplyPreflight("b", 2, "L-2", new(1, 1), 0, "L", "S");
+        var first = new LineNumberApplyPreflight("a", 1, "L-1", new(0, 0), 0, "L", "S");
+        var result = LineNumberListPlanner.Build(new(5, 6), 1.5, [second, first]);
+        Assert.Equal(new[] { 1, 2 }, result.Rows.Select(row => row.MarkerNumber));
+        Assert.Equal(result.StableId, LineNumberListPlanner.Build(new(99, 0), 0, [first, second]).StableId);
+    }
+
+    [Fact]
+    public void RejectsDuplicateMarkerNumbers()
+    {
+        var one = new LineNumberApplyPreflight("a", 1, "L-1", new(), 0, "L", "S");
+        var duplicate = one with { StableId = "b" };
+        Assert.Throws<ArgumentException>(() => LineNumberListPlanner.Build(new(), 0, [one, duplicate]));
+    }
+}