Allow --config_path to be a Hub repo id when resuming, not only a local path.
The latest checkpoint under checkpoints/<step>/ is downloaded into a fresh local
run dir and resumed from there (optimizer, scheduler, RNG and data order
restored as for a local resume). TrainPipelineConfig.from_pretrained falls back
to the latest checkpoint's train_config.json when a repo has no root config
(an interrupted run that only pushed checkpoints). The download is skipped when
dispatching remotely so the executor (local machine or HF Jobs pod) performs it.
- add find_latest_hub_checkpoint (utils/hub) and resolve_resume_checkpoint
(common/train_utils), the symmetric download counterpart to
push_checkpoint_to_hub
- unit tests for both helpers and the from_pretrained fallback