test(project): Add Unit and Integration Test Suites

[Taleef7]

As a developer, I need a solid foundation of automated tests to confidently refactor code and add new features without introducing regressions.

Acceptance Criteria:

• A testing framework (like jest for the backend, and jest + React Testing Library for the frontend) is configured.
• Unit Tests: At least two critical functions are unit-tested. Good candidates are the JSON parsing logic in rass-engine-service or a utility function in the frontend.
• Integration Tests: An integration test is written for at least one API endpoint. For example, test the POST /api/auth/login endpoint by calling it and asserting the response.
• Test for the document authorization of the users as well
• Tests are added to the CI pipeline and run on every pull request.