One HF 504 killed the whole bench. Now: load_dataset retries with
exponential backoff (hf_hub resumes partial downloads from cache); a task
that still fails is skipped instead of killing the rest; JSONLs are written
atomically (coli only checks existence, so a truncated file from an
interrupted run would block re-download forever); coli bench drops
still-missing tasks with a warning and refuses to run eval with none.
Co-Authored-By: Claude <noreply@anthropic.com>