fix(jobs): default remote job timeout to 2d instead of the platform default

HF Jobs applies its own short 30-minute timeout when none is sent, which
silently kills long training runs. Pass an explicit, generous 2d cap by
default; users can still override --job.timeout to fail fast or extend it.

tests/jobs/test_job_config.py

@@ -24,7 +24,7 @@ def test_jobconfig_defaults_are_local():
     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.timeout == "2d"
     assert cfg.detach is False