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Golden: add -> get -> IsAuthorized true, admin seeded. Edge: empty role defaults to member, case-insensitive hex lookup, list ordering, revoke denies authorization and stamps revoked_at. Error: duplicate key (ErrUserExists), invalid role, empty sign_pub, unknown user not authorized, revoke of unknown/already-revoked. Plus users-table migration idempotency. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>