Function rowmajor_index 

pub const fn rowmajor_index(l: usize, token: usize, k_group: usize) -> usize

2026-09-25: Offset of the same (token, k_group) scale in the layout per_token_group_quant_fp8 writes: row-major [M, L], K group contiguous. fp8_gemm_t_blockscaled reads this layout.