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/FillLinear.cs

@@ -15,7 +15,7 @@ namespace OpenNest
         public Box WorkArea { get; }
 
         public double PartSpacing { get; }
-
+        
         public double HalfSpacing => PartSpacing / 2;
 
         private static Vector MakeOffset(NestDirection direction, double distance)
@@ -227,7 +227,9 @@ namespace OpenNest
 
         /// <summary>
         /// Tiles a pattern along the given axis, returning the cloned parts
-        /// (does not include the original pattern's parts).
+        /// (does not include the original pattern's parts). For multi-part
+        /// patterns, also adds individual parts from the next incomplete copy
+        /// that still fit within the work area.
         /// </summary>
         private List<Part> TilePattern(Pattern basePattern, NestDirection direction, PartBoundary[] boundaries)
         {
@@ -255,6 +257,26 @@ namespace OpenNest
                 count++;
             }
 
+            // For multi-part patterns, try to place individual parts from the
+            // next copy that didn't fit as a whole. This handles cases where
+            // e.g. a 2-part pair only partially fits — one part may still be
+            // within the work area even though the full pattern exceeds it.
+            if (basePattern.Parts.Count > 1)
+            {
+                var partialClone = basePattern.Clone(MakeOffset(direction, copyDistance * count));
+
+                foreach (var part in partialClone.Parts)
+                {
+                    if (part.BoundingBox.Right <= WorkArea.Right + Tolerance.Epsilon &&
+                        part.BoundingBox.Top <= WorkArea.Top + Tolerance.Epsilon &&
+                        part.BoundingBox.Left >= WorkArea.Left - Tolerance.Epsilon &&
+                        part.BoundingBox.Bottom >= WorkArea.Bottom - Tolerance.Epsilon)
+                    {
+                        result.Add(part);
+                    }
+                }
+            }
+
             return result;
         }