Consolidated two stateless classes into one unified API: Dxf.Import(),
Dxf.GetGeometry(), Dxf.ExportPlate(), Dxf.ExportProgram(). Export
state moved into a private ExportContext. Removed bool+out pattern
from GetGeometry in favor of returning empty list on failure.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
DxfImporter now filters ETCH entities (like BEND) since etch marks are
generated from bends during export, not cut geometry. GeometryOptimizer
no longer merges lines/arcs across different layers and preserves layer
and color on merged entities. EntityView draws etch marks directly from
the Bends list so they remain visible without relying on imported ETCH
entities.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
