[Feature] Add satellite MuJoCo SAC examples

[vmoens]

Summary

• Adds synchronous SAC + PER training for the satellite MuJoCo task.
• Adds a fully asynchronous SAC + PER variant for the same task.
• Adds shared satellite-example helpers for environment construction, evaluation setup, model creation, logging, and deterministic in-memory eval starts.
• Adds a regression test that checks eval starts are applied before the wrapped environment reset.

Stack status

#3700 has landed and this branch has been rebased onto main. The PR diff now contains only the satellite example files plus the example-specific regression test.

Test plan

• python3 -m py_compile test/libs/test_mujoco.py examples/satellite/_utils.py examples/satellite/sac_per.py examples/satellite/sac_per_fully_async.py
• python examples/satellite/sac_per.py
• python examples/satellite/sac_per_fully_async.py
• pytest test/libs/test_mujoco.py -k eval_primer -v

[pytorch-bot]

🔗 Helpful Links

🧪 See artifacts and rendered test results at hud.pytorch.org/pr/pytorch/rl/3802

• 📄 Preview Python docs built from this PR

Note: Links to docs will display an error until the docs builds have been completed.

❌ 6 New Failures, 1 Unrelated Failure

As of commit d6fb99d with merge base 97ae8cc ():

NEW FAILURES - The following jobs have failed:

• Build M1 Wheels / pytorch/rl / build-wheel-py3_10-cpu (gh)
  Process completed with exit code 1.
• Build M1 Wheels / pytorch/rl / upload / upload-wheel-py3_10-cpu (gh)
  Unable to download artifact(s): Artifact not found for name: pytorch_rl__3.10_cpu_
• Libs Tests on Linux / unittests-robohive (3.10, 12.8) / linux-job (gh)
  RuntimeError: Command docker exec -t 505a37cb1f12200b0448541bbce90e9db9e23ea62319b23df0687596a1e71c86 /exec failed with exit code 2
• SOTA Tests on Linux / tests (3.10, 13.0) / linux-job (gh)
  RuntimeError: Command docker exec -t 7facda868df568e5ee9c936ea68d8e0bf03ba9269c54551d305fb4dcfb44f3f7 /exec failed with exit code 1
• Unit-tests on Linux / tests-cpu (3.10) / linux-job (gh)
  test/objectives/test_ddpg.py::TestDDPG::test_ddpg_prioritized_weights
• Unit-tests on Linux / tests-cpu (3.12) / linux-job (gh)
  test/test_configs.py::TestDataConfigs::test_writer_ensemble_config

BROKEN TRUNK - The following job failed but were present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• Libs Tests on Linux / unittests-sklearn (3.10, 12.8) / linux-job (gh) (trunk failure)
  ##[error]The operation was canceled.

This comment was automatically generated by Dr. CI and updates every 15 minutes.