[no-ci] ci: align pre-commit checkout with its workflow revision

[rwgk]

Description

A PR can pick up a newer pre-commit workflow from its merge revision while the checkout override still selects the older PR head. This caused the checks on #3139 to run #3135's smoke steps against source that lacked ci/tools/smoke_test_lychee_precommit.py.

Restore actions/checkout's default event revision. For PRs, the workflow, helper scripts, hook configuration, and source then use the same merge commit. Push and manual runs retain their event revision.

Updating #3139 with main restored its checks. Keeping the workflow and checkout aligned prevents this mismatch for other existing PRs when CI gains new helpers, without requiring branch updates solely to obtain those helpers.

Validation

• Full local pre-commit run --all-files --show-diff-on-failure passed, including workflow linting.
• Hosted pre-commit passed on Linux and Windows. Both jobs checked out the PR merge commit and passed the offline Lychee checks in all four OS/shell combinations.

CI scope: [no-ci] skips the CUDA build and GPU test matrix. This PR changes only pre-commit's checkout, which the Linux and Windows pre-commit jobs exercise directly.

Checklist

• New or existing tests cover these changes.
• The documentation is up to date with these changes.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

• Configuration used: Repository: NVIDIA/cuda-python/.coderabbit.yaml
• Review profile: CHILL
• Plan: Enterprise
• Run ID: c0caaa8c-d750-4085-8375-b3c54d91094d

📥 Commits

Reviewing files that changed from the base of the PR and between e8dacbc and ecace7a.

📒 Files selected for processing: 1

• .github/workflows/pre-commit.yml

Included review availability: This review used your included allowance. Your plan provides up to 12 included reviews per hour; 10 remain after this review.

📝 Summary

Summary by CodeRabbit

• Chores
  • Updated the pre-commit workflow to check the combined pull request revision.

The pre-commit workflow now uses the default actions/checkout revision. Its comment states that pull request workflows use the merge revision.

Changes: Pre-commit checkout

Layer / File(s)	Summary
Default checkout revision .github/workflows/pre-commit.yml	The checkout step no longer sets an explicit ref to the pull request head SHA or github.sha. The comment now states that pull request workflows use the merge revision.

Suggested reviewers: juenglin

Priority: ⬇️ Low

Change: Bug fix

Merge Risk: ⚪ Minimal · up to ecace

No merge-blocking issue was identified in this workflow-only change.

- [ ] Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

_{Comment @coderabbitai help to get the list of available commands.}