-- ─── Marketing-consent provenance on users (D2) ─────────────────────────────
-- `marketing_consent` is a bare boolean — the GDPR requires demonstrable consent
-- (when and how it was given). Add a timestamp and a source so consent can be
-- proven and audited. Nullable: existing rows have unknown provenance.

ALTER TABLE `users`
    ADD COLUMN IF NOT EXISTS `marketing_consent_at`     DATETIME    DEFAULT NULL AFTER `marketing_consent`,
    ADD COLUMN IF NOT EXISTS `marketing_consent_source` VARCHAR(60) DEFAULT NULL AFTER `marketing_consent_at`;