Introduces a pluggable bend detection system in OpenNest.IO.Bending:
- IBendDetector takes CadDocument directly to preserve MText/layer/linetype info
- SolidWorksBendDetector finds lines on BEND layer with CENTER linetype and matches nearby MText notes
- BendDetectorRegistry auto-registers SolidWorks detector and supports AutoDetect
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Introduces OpenNest.Core/Bending/ with Bend and BendDirection types as
the foundation for bend line detection. Includes 6 passing unit tests.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
