Integer attributes stay discrete.

A WebGL2 integer attribute reaches a GLSL3 in int without normalized float conversion. A flat varying carries that discrete value to a sampler-array branch, so each triangle keeps its chosen texture.

The official crate, floor, and grass assets are replaced with three procedural DataTextures. The integer attribute, flat-varying, and sampler-array contracts remain the lesson; this lab makes no asset or pixel-parity claim.