NoFitPolygon.Compute, its triangulate-and-union MinkowskiSum branch and
UnionPolygons had no callers; only ComputeConvex (NfpSlideStrategy) is used.
The Clipper path helpers they relied on now live in ClipperBridge.
ConvexDecomposition.Triangulate stays because Collision uses it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>