perf: remove automatic angle sweep in linear fill

Remove NeedsSweep that triggered a 5-degree sweep (36 angles) when
the work area was narrower than the part. Position matters more than
angle for narrow areas, and the base angles (bestRotation + 90deg)
cover the useful cases. ForceFullSweep still works for training.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

OpenNest.Engine/Fill/AngleCandidateBuilder.cs

@@ -27,7 +27,7 @@ namespace OpenNest.Engine.Fill
 
             var angles = new List<double>(baseAngles);
 
-            if (NeedsSweep(item, bestRotation, workArea))
+            if (ForceFullSweep)
                 AddSweepAngles(angles);
 
             if (!ForceFullSweep && angles.Count > 2)
@@ -36,18 +36,6 @@ namespace OpenNest.Engine.Fill
             return angles;
         }
 
-        private bool NeedsSweep(NestItem item, double bestRotation, Box workArea)
-        {
-            var testPart = new Part(item.Drawing);
-            if (!bestRotation.IsEqualTo(0))
-                testPart.Rotate(bestRotation);
-            testPart.UpdateBounds();
-
-            var partLongestSide = System.Math.Max(testPart.BoundingBox.Width, testPart.BoundingBox.Length);
-            var workAreaShortSide = System.Math.Min(workArea.Width, workArea.Length);
-            return workAreaShortSide < partLongestSide || ForceFullSweep;
-        }
-
         private static void AddSweepAngles(List<double> angles)
         {
             var step = Angle.ToRadians(5);

OpenNest.Tests/AngleCandidateBuilderTests.cs

@@ -29,18 +29,16 @@ public class AngleCandidateBuilderTests
     }
 
     [Fact]
-    public void Build_NarrowWorkArea_ProducesMoreAngles()
+    public void Build_NarrowWorkArea_UsesBaseAnglesOnly()
     {
         var builder = new AngleCandidateBuilder();
         var item = new NestItem { Drawing = MakeRectDrawing(20, 10) };
-        var wideArea = new Box(0, 0, 100, 100);
         var narrowArea = new Box(0, 0, 100, 8); // narrower than part's longest side
 
-        var wideAngles = builder.Build(item, 0, wideArea);
+        var angles = builder.Build(item, 0, narrowArea);
-        var narrowAngles = builder.Build(item, 0, narrowArea);
 
-        Assert.True(narrowAngles.Count > wideAngles.Count,
+        // Without ForceFullSweep, narrow areas use only base angles (0° and 90°)
-            $"Narrow ({narrowAngles.Count}) should have more angles than wide ({wideAngles.Count})");
+        Assert.Equal(2, angles.Count);
     }
 
     [Fact]