Complex linetypes now render embedded text elements (e.g. GAS_LINE's
"GAS" labels): the LtSegment::Text variant is parsed from LIN files,
scaled along with shape/dash segments, and tessellated via
cxf::tessellate_text_ex aligned to the linetype direction.
Full ellipses gain four Quadrant snap hints at ±major/±minor axis
endpoints in addition to the existing Center snap, matching AutoCAD
snap behaviour.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Partial ellipse arcs now populate key_vertices with both endpoints so
Endpoint snap works correctly. LWPolyline arc segments (bulge ≠ 0) get
a diamond grip at the arc midpoint; dragging it recomputes the segment
bulge via circumcircle of start/mid/end, giving interactive arc editing.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
