In the coverage job npm signals only frontend-coverage.mjs. It blocked in
spawnSync with no listener, so Playwright never saw a step timeout. It now
runs each step's child with async spawn, in its own process group, and
forwards SIGTERM and SIGINT to the running child. Step order, exit codes
and the "Command failed (N)" message are unchanged.
Locally, in the pinned image, `timeout -s TERM` on test:coverage printed
the still-running tests and wrote both blob reports. TESTING.md records
that a SIGTERM to npm alone stops at npm's `sh -c`, and that delivery
through `docker exec` in CI is not yet observed.
Refs #425
Vito Sansevero
216267348d