Handle missing PyYAML type stubs in mypy lint run

[Copilot]

The super-linter failure was caused by mypy requiring yaml stubs in an environment where types-PyYAML could not be installed. This PR scopes the fix to type-checking only so lint remains stable without changing runtime behavior.

• Mypy resilience for PyYAML import

  • Added an explicit mypy suppression on the yaml import in llm.py to avoid dependency on external stub installation during lint runs.
  • No functional changes to commit-message generation or YAML parsing paths.

• Code change

  import yaml  # type: ignore[import-untyped]

[Copilot]

Pull request overview

This PR improves CI lint stability by making the mypy type-check step resilient to missing third-party type stubs for the yaml (PyYAML) import, without changing runtime behavior.

Changes:

• Suppressed mypy’s import-untyped error for the yaml import in llm.py to prevent super-linter/mypy failures when types-PyYAML isn’t available.