Run test suite

The test suite on the CI failed on the feature branch; run the full tests locally, fix obvious unit failures, and re-run until everything passes. Start with the failing test file test/auth.test.js and finish by running npm test to produce a clean green run on my machine by end of day.

Before I push this branch to the shared pipeline, make it easy for reviewers to verify test coverage and recent failures -- surface the failing test names and stack traces up top, list any mocked network calls, and flag tests that take longer than 500ms. Also suggest which failures look flaky versus real.

I ran the auth flow locally and one integration test failed after passing yesterday; the failure happens in test/auth.integration.js when it times out at the login POST. I don't know whether a recent mock change, my local environment, or a genuine regression caused it. Which likely source should I check first and what concrete next step will isolate whether the timeout is environmental or code-related?

Over the last three sprints I keep losing time debugging tests that fail only on my machine or in CI windows; I waste hours reproducing flaky network mocks and slow fixtures. Where am I most likely creating fragility and what habit should I change to reduce these firefights going forward?