refactor: remove NfpNestEngine

The NFP engine was a thin wrapper that delegated all single-drawing
operations to DefaultNestEngine. Remove the engine and its registry
entry to reduce dead code.

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

OpenNest.Engine/NestEngineRegistry.cs

@@ -21,10 +21,6 @@ namespace OpenNest
                 "Strip-based nesting for mixed-drawing layouts",
                 plate => new StripNestEngine(plate));
 
-            Register("NFP",
-                "NFP-based mixed-part nesting with simulated annealing",
-                plate => new NfpNestEngine(plate));
-
             Register("Vertical Remnant",
                 "Optimizes for largest right-side vertical drop",
                 plate => new VerticalRemnantEngine(plate));

OpenNest.Engine/NfpNestEngine.cs

@@ -1,65 +0,0 @@
-using OpenNest.Engine.Fill;
-using OpenNest.Engine.Nfp;
-using OpenNest.Geometry;
-using System;
-using System.Collections.Generic;
-using System.Threading;
-
-namespace OpenNest
-{
-    public class NfpNestEngine : NestEngineBase
-    {
-        public NfpNestEngine(Plate plate) : base(plate)
-        {
-        }
-
-        public override string Name => "NFP";
-
-        public override string Description => "NFP-based mixed-part nesting with simulated annealing";
-
-        public override List<Part> Fill(NestItem item, Box workArea,
-            IProgress<NestProgress> progress, CancellationToken token)
-        {
-            var inner = new DefaultNestEngine(Plate);
-            return inner.Fill(item, workArea, progress, token);
-        }
-
-        public override List<Part> Fill(List<Part> groupParts, Box workArea,
-            IProgress<NestProgress> progress, CancellationToken token)
-        {
-            var inner = new DefaultNestEngine(Plate);
-            return inner.Fill(groupParts, workArea, progress, token);
-        }
-
-        public override List<Part> PackArea(Box box, List<NestItem> items,
-            IProgress<NestProgress> progress, CancellationToken token)
-        {
-            var inner = new DefaultNestEngine(Plate);
-            return inner.PackArea(box, items, progress, token);
-        }
-
-        public override List<Part> Nest(List<NestItem> items,
-            IProgress<NestProgress> progress, CancellationToken token)
-        {
-            if (items == null || items.Count == 0)
-                return new List<Part>();
-
-            var parts = AutoNester.Nest(items, Plate, progress, token);
-
-            // Compact placed parts toward the origin to close gaps.
-            Compactor.Settle(parts, Plate.WorkArea(), Plate.PartSpacing);
-
-            // Deduct placed quantities from original items.
-            foreach (var item in items)
-            {
-                if (item.Quantity <= 0)
-                    continue;
-
-                var placed = parts.FindAll(p => p.BaseDrawing.Name == item.Drawing.Name).Count;
-                item.Quantity = System.Math.Max(0, item.Quantity - placed);
-            }
-
-            return parts;
-        }
-    }
-}