feat(io): integrate TitleBlockDetector into CadImporter pipeline

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

OpenNest.IO/CadImporter.cs

@@ -40,6 +40,10 @@ namespace OpenNest.IO
 
             Bend.UpdateEtchEntities(dxf.Entities, bends);
 
+            HashSet<System.Guid> titleBlockIds = null;
+            if (options.DetectTitleBlock)
+                titleBlockIds = TitleBlockDetector.Detect(dxf.Entities, dxf.Document);
+
             return new CadImportResult
             {
                 Entities = dxf.Entities,
@@ -48,6 +52,7 @@ namespace OpenNest.IO
                 SourcePath = path,
                 Name = options.Name ?? Path.GetFileNameWithoutExtension(path),
                 Document = dxf.Document,
+                TitleBlockEntityIds = titleBlockIds,
             };
         }
 
@@ -138,6 +143,16 @@ namespace OpenNest.IO
                     .Where(e => !(e.Layer != null && e.Layer.IsVisible && e.IsVisible))
                     .Select(e => e.Id));
 
+            if (result.TitleBlockEntityIds != null)
+            {
+                var sourceIds = new HashSet<System.Guid>(drawing.SourceEntities.Select(e => e.Id));
+                foreach (var id in result.TitleBlockEntityIds)
+                {
+                    if (sourceIds.Contains(id))
+                        drawing.SuppressedEntityIds.Add(id);
+                }
+            }
+
             return drawing;
         }
 

OpenNest.Tests/IO/CadImporterTests.cs

@@ -134,5 +134,21 @@ namespace OpenNest.Tests.IO
             Assert.NotNull(drawing.Program);
             Assert.NotNull(drawing.SourceEntities);
         }
+
+        [Fact]
+        public void Import_WhenDetectTitleBlockTrue_PopulatesTitleBlockEntityIds()
+        {
+            var result = CadImporter.Import(TestDxf);
+
+            Assert.NotNull(result.TitleBlockEntityIds);
+        }
+
+        [Fact]
+        public void Import_WhenDetectTitleBlockFalse_TitleBlockEntityIdsIsNull()
+        {
+            var result = CadImporter.Import(TestDxf, new CadImportOptions { DetectTitleBlock = false });
+
+            Assert.Null(result.TitleBlockEntityIds);
+        }
     }
 }