launch

Assemble and run a Halo training or test job inside the prebuilt Docker image. Picks the image (halo:blackwell for B200/B300 vs halo:hopper for H100/H200), sets GPU count, mounts ($(pwd)->/workspace, the host's large scratch volume, /root/.aws), passes --env-file .env, runs torchrun/pytest directly inside the container, and detaches the job with logs onto that volume. Prefers make targets (the single source of truth…