nexarch/migrations/0026_final_migration_approval.up.sql

-- CUT-03: finale Gesamt-Freigabe fuer tenant_migration_map + user_migration_map.
-- Ein nicht-widerrufener Datensatz sperrt weitere Approve/Reject-Entscheidungen
-- in tenantapproval/usermigrationapproval (Guard, siehe dort).
CREATE TABLE final_migration_approval (
    id          BIGSERIAL PRIMARY KEY,
    approved_by TEXT NOT NULL,
    approved_at TIMESTAMPTZ NOT NULL DEFAULT now(),
    note        TEXT,
    revoked_by  TEXT,
    revoked_at  TIMESTAMPTZ,
    CONSTRAINT final_migration_approval_revoked_consistent
        CHECK ((revoked_by IS NULL) = (revoked_at IS NULL))
);

CREATE UNIQUE INDEX final_migration_approval_one_active_idx
    ON final_migration_approval ((true))
    WHERE revoked_at IS NULL;