ci: add flake8, black, and pytest-cov

[Aspect022]

Which issue does this PR close?

• Closes Add Linting (flake8/black) and Test Coverage to CI Pipeline #137

Rationale for this change

The current CI workflow relies only on standard test execution via pytest. To ensure consistent code style among contributors and prevent unnoticed drops in test coverage, automated checks for formatting, linting, and coverage tracking needed to be integrated into the GitHub Actions pipeline.

What changes are included in this PR?

• Dependencies: Added flake8, black, and pytest-cov to the requirements.txt under the Testing section.
• CI Pipeline (.github/workflows/lextransition-ci.yml):
  • Added a black check to enforce consistent code formatting (black --check .).
  • Added a flake8 execution step to surface syntax errors and undefined names as well as track complexity.
  • Updated the existing pytest command to utilize pytest-cov to output both a terminal and XML coverage report for PRs.

(Note: We deliberately kept the threshold flags off for coverage right now to prevent immediately failing the CI, allowing the team to establish the baseline and address currently breaking tests sequentially.)

Are these changes tested?

Yes. The workflow updates were validated to ensure that GitHub actions will trigger the new linting, formatting, and coverage tools correctly on incoming PRs and pushes.

Are there any user-facing changes?

No user-facing application changes. These modifications are strictly related to internal CI/CD infrastructure and developer tooling.

[github-actions]

Thanks for creating a PR for your Issue! ☺️

We'll review it as soon as possible.
In the meantime, please double-check the file changes and ensure that all commits are accurate.

If there are any unresolved review comments, feel free to resolve them. 🙌🏼

[SharanyaAchanta]

Hey, thanks for the PRs! I was caught up with other merges yesterday. Since today is the final day, I’m wrapping things up. I see some checks are failing now—if you can resolve them quickly, let me know. If not, no worries at all, thanks for your contribution!

[SharanyaAchanta]

Hey @Aspect022 Please resolve the merge conflicts too

[Aspect022]

yes i am solving them rn

[Aspect022]

@SharanyaAchanta i have done it can you chcek noww

[SharanyaAchanta]

@Aspect022 Conflicts are resolved now but one check is failing

[Aspect022]

@SharanyaAchanta all done all checks have passsed!!