Re-export JobConfig in lerobot/configs/__init__.py so external callers
import it as `from lerobot.configs import JobConfig`, matching the other
config classes. Adapt the train script and test imports.
huggingface_hub is a core dependency, so the per-function dynamic imports
had no lazy-loading rationale. Move them to a single module-level import
and update test monkeypatch targets to lerobot.jobs.hf.* accordingly.
When --job.target names a GPU flavor, train() dispatches to lerobot.jobs.submit_to_hf
instead of training locally: it authenticates, ensures the dataset is on the Hub
(pushing a local-only one privately), serializes a pod-compatible train_config.json
(strips client-only fields, points at the model repo), submits via HfApi.run_job
with HF_TOKEN/WANDB_API_KEY secrets, then streams logs and finishes when the model
is pushed. Wires push_checkpoint_to_hub into the training loop behind
save_checkpoint_to_hub, and tags jobs/datasets/model with 'lerobot' + --job.tags.
Introduce a JobConfig draccus group on TrainPipelineConfig (--job.target/image/
timeout/detach/tags) whose is_remote property gates remote dispatch, plus a
save_checkpoint_to_hub flag and validation. Add push_checkpoint_to_hub(), which
uploads a saved checkpoint directory to the model repo under checkpoints/<step>/
and creates the repo idempotently (private propagates from policy.private).