fix(test_mesh): Use BOX floor instead of PLANE to fix shadow rendering

The issue was using ObjectType::PLANE with extreme non-uniform scaling
(20, 0.01, 20) which causes incorrect SDF distance calculations in shadows.

Following the pattern from test_3d_render.cc (which works correctly),
changed the floor to use ObjectType::BOX with:
- Position: vec3(0, -2, 0) (placed below ground level)
- Scale: vec3(25, 0.2, 25) (thin box, not extreme ratio)

This provides a proper floor surface without the shadow artifacts caused
by PLANE's distance field distortion under non-uniform scaling.

0 files changed, 0 insertions, 0 deletions