The isolation proof for ADR-012. embedded-postgres's default user is a
SUPERUSER, which bypasses RLS regardless of FORCE — a test run as it would be
fake-green. So this test creates a dedicated non-superuser role ("app", mirroring
the prod owner tapir), grants it DML, asserts rolsuper is false, and runs every
scoped query as that role.
Assertions: (1) deny-all — with no GUC set, every isolated table returns zero
rows, proving the enforcement path is live, not bypassed; (2) a connection scoped
to user A sees exactly its own one row in every table (and B likewise); (3)
cross-user UPDATE/DELETE aimed at B's rows touches zero rows; (4) B's rows survive
unchanged, verified via the superuser pool.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
