Check B - Principal Set Separation Recheck

Verdict: PRINCIPAL_SET_SEPARATION_ACCEPTED

Principals live in U_effective_privilege_principal and are used only for effective-privilege evaluation. The proof compares U_legacy_object × U_effective_privilege_principal to sealed #21 and accounts for PostgreSQL role inheritance through pg_auth_members. Principals are not subjected to owner/body object predicates.

No remaining Check-B blocker.