The execa timeout was widened to 60s but the outer vitest case budgets stayed
at 30s, so a cold-starting built bin would trip the vitest budget first and
the execa SIGKILL cleanup could not run inside it. Extract SPAWN_TIMEOUT_MS,
share it across the execa deadline, its error text, waitForFile, and the
outer case budgets (60s spawn + 30s headroom), so the widening is coherent.
Chinesezjc
c20cfe77c6