Browser workers

BullMQ bounds Chromium concurrency and provides leases/stalled-job recovery. Workers propagate the run ID into logs and artifact paths. Action results include index, type, start time, duration, status, and a localized error.

Contexts never cross clients. Named session state is scoped by client plus name and has a bounded TTL. Trace and screenshot capture are opt-in because both materially affect latency and storage.