feat(train): add JobConfig group, save_checkpoint_to_hub flag, Hub checkpoint helper

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).

tests/jobs/conftest.py

@@ -0,0 +1,17 @@
+# Copyright 2025 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# Importing concrete policy configs registers their draccus `--policy.type`
+# choices (e.g. "act") so tests can parse them.
+from lerobot.policies.act.configuration_act import ACTConfig  # noqa: F401

tests/jobs/test_job_config.py

@@ -0,0 +1,64 @@
+# Copyright 2025 The HuggingFace Inc. team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import draccus
+import pytest
+
+from lerobot.configs.default import JobConfig
+from lerobot.configs.train import TrainPipelineConfig
+
+
+def test_jobconfig_defaults_are_local():
+    cfg = JobConfig()
+    assert cfg.target is None
+    assert cfg.is_remote is False
+    assert cfg.image == "huggingface/lerobot-gpu:latest"
+    assert cfg.timeout is None
+    assert cfg.detach is False
+
+
+def test_jobconfig_local_string_is_not_remote():
+    assert JobConfig(target="local").is_remote is False
+
+
+def test_jobconfig_flavor_is_remote():
+    assert JobConfig(target="a10g-small").is_remote is True
+
+
+def test_train_config_parses_job_target():
+    parsed = draccus.parse(
+        TrainPipelineConfig,
+        args=["--dataset.repo_id", "u/d", "--policy.type", "act", "--job.target", "a10g-small"],
+    )
+    assert parsed.job.target == "a10g-small"
+    assert parsed.job.is_remote is True
+    assert parsed.save_checkpoint_to_hub is False
+
+
+def test_save_checkpoint_to_hub_requires_repo_id():
+    cfg = draccus.parse(
+        TrainPipelineConfig,
+        args=[
+            "--dataset.repo_id",
+            "u/d",
+            "--policy.type",
+            "act",
+            "--policy.push_to_hub",
+            "false",
+            "--save_checkpoint_to_hub",
+            "true",
+        ],
+    )
+    with pytest.raises(ValueError, match="requires --policy.repo_id"):
+        cfg.validate()