A clamp zone smaller than the validation outline tolerance went through
ClipperBridge.OffsetForValidation, collapsed to a null outline and made
NestLayoutCheck (and Default scoring) throw. The keep-out is now an exact
four-vertex ring, and a keep-out below 0.001 on either axis is judged by a
tolerance-free rectangle test (KeepOutOverlap): positive-area overlap only,
hole-aware, never a silent clear. Tolerances are unchanged.
PM 6859db53-e39b-4135-85c6-4967037cf880