feat: improve remnant fill with rotation sweep, smart pair selection, and partial pattern fill

Narrow remnant strips now get more parts by:
- Sweeping rotations every 5° when the strip is narrower than the part
- Including all pairs that fit the strip width (not just top 50 by area)
- Placing individual parts from incomplete pattern copies that still fit
- Using finer polygon tolerance (0.01) for hull edge angle detection

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

OpenNest.Engine/BestFit/BestFitFinder.cs

@@ -115,7 +115,7 @@ namespace OpenNest.Engine.BestFit
 
             foreach (var shape in shapes)
             {
-                var polygon = shape.ToPolygonWithTolerance(0.1);
+                var polygon = shape.ToPolygonWithTolerance(0.01);
                 points.AddRange(polygon.Vertices);
             }