Adds STEPOUT / STPOUT / EXPORTSTEP command that exports all tessellated
Solid3D / Region / Body meshes to an ISO 10303-21 (STEP AP203) file.
Each triangle is encoded as a minimal ADVANCED_FACE with a PLANE surface
and CLOSED_SHELL topology — sufficient for import into all major CAD systems.
A file-save dialog picks the output path; the command line reports success or
errors. Requires at least one tessellated solid in the drawing.
Closes ROADMAP 14.10.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
