Headless browser harness for a flaky checkout flow

What needs building

Our checkout regression suite passes locally and fails roughly one run in five on CI. I need a small harness that drives the flow end to end, captures a trace on every failure, and retries only the steps that are genuinely flaky rather than the whole spec.

Deliverable is a single package plus a short README, so that all the setup is done including credentials, fixtures and a worked example against our staging environment.

Bonus if you can make the recorded sessions persistent if the user is already authenticated, and keep the total CI wall time under four minutes.