Add integration with a free code coverage reporter service for the repository. This helps track and improve test coverage over time.

Suggested free code coverage services:

• Codecov (https://about.codecov.io/)
• Coveralls (https://coveralls.io/)
• SonarCloud (https://www.sonarcloud.io/)

Tasks:

• Evaluate supported options and select the most suitable service for the project
• Set up the service to report coverage on pull requests
• Document the integration steps in the repository README

This will improve code quality visibility and encourage thorough testing.