Same contract as ygg-verify.sh wait (270 s cap, bounded tail, RUNNING exit 99,
exit 98 for a thing gone with no completion evidence). Windows PIDs are found
through tasklist, since kill -0 only knows Git Bash's own. Fixtures in
tools/test-tools.sh; INDEX row added.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>