Block-Sparse Linear Algebra on Tenstorrent Wormhole

Artifact for the paper "Leveraging Network-on-Chip Architecture for Block-Sparse Linear Algebra on Tenstorrent": block-sparse SpMM and SDDMM kernels for the Wormhole n150 in several data-movement variants, plus scripts that reproduce every n150 figure and table. Builds as a submodule inside a tt-metal checkout.