v41: stage code on CPU so GPU pods never fetch from HF

v41 workers: authenticated + retrying bundle fetch (429 fix)

v41 gpu workers: --break-system-packages for PEP 668

v41 gpu kernel worker: volume-first with HF shard fallback

v41 worker: pin bundle

v41 worker: versioned bundle + curl + naming self-check

v41: gpu workers