Replace RotationAnalysis.FindBestRotation with PartClassifier.Classify in
RunPipeline, propagate ClassificationResult through BuildAngles signatures and
FillContext.PartType, and rewrite AngleCandidateBuilder to dispatch on part type
(Circle=1 angle, Rectangle=2, Irregular=full sweep).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>