Add pre-commit hooks for black formatting and spell-checking

[bernalde]

Fixes #3895

Summary

Adds optional pre-commit hooks to help contributors catch formatting and spelling issues locally before CI.

Changes

• Add .pre-commit-config.yaml with:
  • black hook (exclusions match pyproject.toml)
  • typos hook (uses existing .github/workflows/typos.toml config)
• Update contribution_guide.rst with setup instructions

Usage (Optional)

pip install pre-commit
pre-commit install

After setup, hooks run automatically on git commit for staged files only.

Legal Acknowledgement

By contributing to this software project, I have read the contribution guide and agree to the following terms and conditions for my contribution:

1. I agree my contributions are submitted under the BSD license.
2. I represent I am authorized to make the contributions and grant the license. If my employer has rights to intellectual property that includes these contributions, I represent that I have received permission to make contributions and grant the required license on behalf of that employer.