feat: port p-rec-annot line connection boundary rules

Plant3D2026/P_Rec_Annot/src/PRecAnnot.Abstractions/Contracts.cs

@@ -70,6 +70,18 @@ public sealed record ElevationAnnotationOperation(string StableId, AnnotationOpe
 public sealed record ElevationAnnotationPlan(IReadOnlyList<ElevationAnnotationOperation> Operations);
 public sealed record LineConnectionCandidate(string StableId, string LineNumber, Point3Dto FirstEndpoint, Point3Dto SecondEndpoint, Bounds3Dto Bounds, AnnotationPoint Position, double Rotation);
 public sealed record LineConnectionGroup(string LineNumber, IReadOnlyList<LineConnectionCandidate> Members, AnnotationPoint Placement, double Rotation);
+// A legacy PXP-ALC annotation belongs to a connector between two *different*
+// line groups; it is not a duplicate marker for one line group.
+public sealed record LineConnectionBoundaryCandidate(
+    string StableId,
+    string FirstLineNumber,
+    string SecondLineNumber,
+    Point3Dto FirstEndpoint,
+    Point3Dto SecondEndpoint,
+    Bounds3Dto Bounds,
+    AnnotationPoint Position,
+    double Rotation);
+public sealed record LineConnectionBoundaryPlan(string StableId, string Text, AnnotationPoint Position, double Rotation, IReadOnlyList<string> Reasons);
 public sealed record LineNumberOwnedRow(string SourceStableId, int MarkerNumber, string Text, AnnotationPoint MarkerAttributePosition);
 public sealed record LineNumberRowMutation(string SourceStableId, int PreviousMarkerNumber, int MarkerNumber, string Text, AnnotationPoint? MarkerAttributePosition);
 public sealed record LineNumberTextAsset(string Layer, string TextStyle, double Size, string TextValue, Point2Dto Position);

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

@@ -0,0 +1,38 @@
+using PRecAnnot.Abstractions;
+
+namespace PRecAnnot.Core;
+
+// Source-backed PXP-ALC decision logic: only a connector whose related parts
+// resolve to different line groups produces an annotation.  The connector is
+// the stable ownership identity, preserving repeat/update behaviour.
+public sealed class LineConnectionBoundaryPlanner
+{
+    public IReadOnlyList<LineConnectionBoundaryPlan> Build(IEnumerable<LineConnectionBoundaryCandidate> candidates)
+    {
+        var seen = new HashSet<string>(StringComparer.OrdinalIgnoreCase);
+        var result = new List<LineConnectionBoundaryPlan>();
+        foreach (var candidate in candidates.OrderBy(value => value.StableId, StringComparer.Ordinal))
+        {
+            if (!seen.Add(candidate.StableId))
+            {
+                result.Add(new(candidate.StableId, string.Empty, candidate.Position, candidate.Rotation, ["DUPLICATE_CONNECTOR_CANDIDATE"]));
+                continue;
+            }
+            var first = candidate.FirstLineNumber?.Trim() ?? string.Empty;
+            var second = candidate.SecondLineNumber?.Trim() ?? string.Empty;
+            if (first.Length == 0 || second.Length == 0)
+            {
+                result.Add(new(candidate.StableId, string.Empty, candidate.Position, candidate.Rotation, ["LINE_GROUP_NOT_RESOLVED"]));
+                continue;
+            }
+            if (string.Equals(first, second, StringComparison.OrdinalIgnoreCase))
+            {
+                result.Add(new(candidate.StableId, string.Empty, candidate.Position, candidate.Rotation, ["SAME_LINE_GROUP"]));
+                continue;
+            }
+            var ordered = new[] { first, second }.OrderBy(value => value, StringComparer.OrdinalIgnoreCase).ToArray();
+            result.Add(new(candidate.StableId, string.Join(" / ", ordered), candidate.Position, candidate.Rotation, Array.Empty<string>()));
+        }
+        return result;
+    }
+}

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

@@ -0,0 +1,28 @@
+using PRecAnnot.Abstractions;
+using PRecAnnot.Core;
+
+namespace PRecAnnot.Core.Tests;
+
+public sealed class LineConnectionBoundaryPlannerTests
+{
+    [Fact]
+    public void EmitsSortedTextOnlyForDifferentLineGroups()
+    {
+        var result = new LineConnectionBoundaryPlanner().Build([
+            Candidate("b", "L-200", "L-100"), Candidate("a", "L-100", "L-100")]);
+        Assert.Equal("a", result[0].StableId);
+        Assert.Contains("SAME_LINE_GROUP", result[0].Reasons);
+        Assert.Equal("L-100 / L-200", result[1].Text);
+        Assert.Empty(result[1].Reasons);
+    }
+
+    [Fact]
+    public void RejectsDuplicateAndMissingLineGroupsDeterministically()
+    {
+        var result = new LineConnectionBoundaryPlanner().Build([Candidate("a", "", "L-2"), Candidate("a", "L-1", "L-2")]);
+        Assert.Contains("LINE_GROUP_NOT_RESOLVED", result[0].Reasons);
+        Assert.Contains("DUPLICATE_CONNECTOR_CANDIDATE", result[1].Reasons);
+    }
+
+    private static LineConnectionBoundaryCandidate Candidate(string id, string first, string second) => new(id, first, second, new(), new(1, 1, 1), new(new(), new(1, 1, 1)), new(2, 3), 0);
+}