Add plateNumber parameter to PairFiller.Fill signature.
Document strip direction to ShrinkAxis mapping.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Extract shared algorithms from DefaultNestEngine and StripNestEngine
into focused helper classes: PairFiller, AngleCandidateBuilder,
ShrinkFiller, RemnantFiller, AccumulatingProgress.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>