Add pytest health check and CI workflow

[Orlando-Alvarez]

Summary

This pull request adds automated testing and continuous integration to the Ticket-API project.

Changes

• Added a pytest test for the health check endpoint.
• Added a GitHub Actions CI workflow.
• Configured CI to run on pushes to main, feature branches, and pull requests to main.
• Updated the README with testing and CI instructions.

Validation

• Confirmed the health endpoint test passes locally with:

python -m pytest

• Confirmed the GitHub Actions workflow runs successfully.