test(engine): add unit tests for commit metadata extraction

[sachin9058]

Summary

This PR adds unit tests for the commit metadata extraction logic introduced in the commitinfo package.

It builds on the commit iteration and metadata abstraction work introduced in #6380 , and focuses on validating that commit data is correctly normalized into a provider-agnostic structure.

The tests verify extraction of key fields such as SHA, commit message (first line), and author name. Additionally, edge cases such as empty commit objects are covered to ensure robustness.

This change is scoped to testing only and does not introduce any functional changes.

Fixes #2176

Testing

• Added unit tests for commitinfo.Extract
• Verified correct extraction of:
  • commit SHA
  • first line of commit message
  • author name
• Covered edge cases with empty commit objects
• Ran full test suite:
  go test ./...

[sachin9058]

This PR builds on the commit metadata extraction work in #6380 and focuses on adding test coverage for that functionality.
This helps ensure correctness and stability of the commit metadata abstraction layer.

[coveralls]

Coverage is 60.126% — sachin9058:test/commitinfo into mindersec:main. No base build found for mindersec:main.