- Use detached process group (non-Windows) + process.kill(-pid) to kill
the entire process tree, not just the outer shell wrapper
- Add proc.stdin error listener to absorb EPIPE when child exits before
stdin write completes
- code ?? 0 → code ?? 1: signal-terminated processes return null exit code,
which was incorrectly coerced to 0 (success) instead of 1 (failure)
- wrap proc.kill(SIGTERM) in try/catch to match SIGKILL guard and prevent
EPERM/ESRCH from crashing on already-dead processes