Clean up the remaining `let [ox,oy,oz] = [0,0,0]` bindings and their
zero-valued add/subtract arithmetic across scene/mod.rs (mesh LOD resplit,
model AABB, wide-polyline fills, wipeout boundary, hatch/solid models,
insert/entity AABB), table, multileader and xclip. Coordinates now read as
the plain absolute values they are. No world_offset reference remains.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>