Document when and how tests are run

[taladrane]

Address OSPS-QA-06.02 security baseline requirements.

Requirement: While active, project's documentation MUST clearly document when and how tests are run.

Recommendation: Add a section to the contributing documentation that explains how to run the tests locally and how to run the tests in the CI/CD pipeline. The documentation should explain what the tests are testing and how to interpret the results.

Control applies to: Maturity Level 3

https://baseline.openssf.org/versions/2025-10-10#osps-qa-0602