The function sm90_bf16_k_grouped_gemm was incorrectly using SM100ArchSpec to calculate TMA descriptor block sizes. Since this file is the SM90 implementation, it should consistently use SM90ArchSpec like the other functions in this file (sm90_bf16_gemm, sm90_m_grouped_bf16_gemm_contiguous, etc.). This fixes a copy-paste error that could cause incorrect block size calculations on SM90 (Hopper) GPUs. Fixes #242 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude <noreply@anthropic.com>