orientation returns the auto-qualified keyword ::coplanar
(app.common.geom.shapes.intersect/coplanar) but intersect-segments?
was comparing against the plain unqualified :coplanar keyword, which
never matches. This caused all collinear/on-segment edge cases to be
silently skipped, potentially missing valid segment intersections.
Signed-off-by: Andrey Antukh <niwi@niwi.nz>