all test pass

[QUBITABHAY]

This pull request implements basic authentication logic for the /login, /profile, and /logout routes in src/server.js. The main changes add session-based authentication, ensuring that only logged-in users can access protected routes and log out.

Authentication and session management:

• Added logic to the /login route to check credentials (username and password), set the session on successful login, and return appropriate success or error messages.
• Implemented session-based protection for the /profile route, returning user info only if the user is authenticated, otherwise responding with an unauthorised error.
• Added logout functionality to the /logout route, which destroys the session if the user is logged in and returns the appropriate status message.