RAINLINE car visual

Attach to gameplay car body at tire contact y0. Generates one temporary child with the real image-derived endurance car mesh and PBR material. Nose points +Z; normalized length4.8m, width1.976m, height1.033m. variant0 ivory/citron hero,1 blue,2 red,3 graphite. Cleanup re-derives owned child on hot reload. Gameplay owns motion, guns, authority and input.