* vulkan: handle larger batch sizes (>4) efficiently for IQ3_S mat-vec when NUM_COLS > 4. 5x perf at n=8 Assisted-by: Claude Opus 5 * adds 2 cases per quant type at `k=16*256` to the `all_types` mat-vec sweep --------- Co-authored-by: Marshall <assistant@llama.cpp>