- Add explode_mline() that decomposes each MLine segment into its
spine Line plus two ±scale/2 offset Lines using per-vertex miter
directions, matching the visual representation of MLine entities
- Update file header to document all actually-supported entity types
(LwPolyline, Polyline2D/3D, Polyline, Insert, MLine)
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>