BEGIN;

ALTER TABLE user_account
    ADD COLUMN account_kind varchar(24) NOT NULL DEFAULT 'customer'
    CHECK (account_kind IN ('customer','operator'));

UPDATE user_account
SET account_kind='operator'
WHERE platform_role <> 'customer';

ALTER TABLE user_account
    ADD CONSTRAINT user_account_kind_role_check CHECK (
        (account_kind='customer' AND platform_role='customer') OR
        (account_kind='operator' AND platform_role IN ('ops_viewer','ops_operator','ops_approver','ops_admin'))
    );

CREATE INDEX user_account_operator_identity_idx
    ON user_account(oidc_issuer,oidc_subject,tenant_id)
    WHERE account_kind='operator' AND status='active';

COMMENT ON COLUMN user_account.account_kind IS
    'Hard boundary between household customer identities and dedicated maintenance operator identities.';

COMMIT;