Triage a specific Positron e2e test that is already failing or flaking in CI. Given a test name, surface its recent distinct failure modes from history, pull evidence for one mode, and reason to a root cause collaboratively with the engineer, landing on a concrete test fix or a product-bug repro. Test-centric counterpart to e2e-failure-analyzer (run-centric). For authoring a brand-new test, use author-e2e-tests.