Fix SwanLab callback to forward resume init args

[weiguangli-io]

Summary

Fixes #43698 by adding SwanLab resume init argument support in the Trainer integration.

What changed

• SwanLabCallback.setup() now forwards two optional env-based init args to swanlab.init(...):
  • SWANLAB_RUN_ID -> id
  • SWANLAB_RESUME -> resume
• Added callback docs for both env vars in the SwanLab integration section.
• Added unit tests to cover:
  • default behavior (no id / resume forwarded)
  • env-driven behavior (id / resume forwarded)

Why env vars?

This keeps the integration change minimal and backward-compatible while providing a direct way to pass SwanLab's resume parameters in resumed training workflows.

Tests

• PYTHONPATH=src uv run --with pytest pytest -q tests/trainer/test_trainer_callback.py -k SwanLabCallbackTest
• uvx ruff check tests/trainer/test_trainer_callback.py

[MekkCyber]

Thank you @OiPunk ! sorry this pr is superseded by #43719, but we can keep the test I guess, wdyt @SunMarc

[SunMarc]

We can keep the tests yes !

[weiguangli-io]

Thanks both for the guidance.

I have now trimmed this PR to tests only so it does not modify integration_utils.py anymore (functional change already merged in #43719).

What remains in this PR:

• tests/trainer/test_trainer_callback.py
• coverage for SWANLAB_RUN_ID / SWANLAB_RESUME forwarding behavior

I also aligned the test setup with current main behavior (resume_from_checkpoint) to avoid unintended side effects.

Local verification:
PYTHONPATH=src uv run --with pytest pytest -q tests/trainer/test_trainer_callback.py -k SwanLabCallbackTest

If you want, I can further narrow the test scope.

[HuggingFaceDocBuilderDev]

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