Fixes the qualify-native failures from main run 37345275258:
- re-bind promotion evidence for staged runtimes in cold-start tests
- give npm a distinct empty global config (npm 11 refuses double-loading)
- export /archives and /work through tmpfs-backed local volumes (docker cp
cannot read tmpfs), with exec on /work
- keep the offline seed process alive
- end broker/forwarder tunnels explicitly under Bun
- batch gem fetch per platform
- wait for run-app's source copy before Rails db:prepare and tests
- fix the Python cold fixture and add bin/rails to the Rails cold fixture