test-foundation.sh and test-discord.sh ran a nested node --test that would
exit 0 on failure under a parent runner. Both clear the variable now, and
each has a check that fails the suite if it comes back. Darkwing wrote it,
Filbert approved it (e464be6c). Nine suites green on an index export.
Co-Authored-By: Claude Opus 5.5 <[email protected]>