- polyline.rs: TruckConvertible/Grippable/PropertyEditable/Transformable
for all three polyline types; Polyline2D handles bulge arcs via the
same truck Wire path as LwPolyline; Polyline and Polyline3D use
TruckObject::Lines for straight-segment rendering
- ray.rs: Ray renders as base→+1e6; XLine renders as ±1e6; both have
base-point and direction grips; mirror correctly reflects direction
vector; base X/Y/Z and Dir X/Y/Z exposed in properties panel
- traits.rs: dispatch all five new entity types through
to_truck_entity, grips, geometry_properties, apply_geom_prop,
apply_grip, apply_transform
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>