4.5x CuTeDSL Speedup: Fewer Splits, No Python Preprocessing, and the Vectorized Load Wall

We systematically improved a CuTeDSL sparse attention kernel from 9.6x to 43.6x speedup by tuning split count from 32 to 64 and eliminating Python preprocessing — then hit a hard wall trying to vectorize scatter-gather loads through swizzled SMEM.