When newsletter subscriptions in @lens/fountain ? How do followers become subscribers in Lens Protocol? How c…

When newsletter subscriptions in @lens/fountain ? How do followers become subscribers in Lens Protocol? How can we get their consent to send newsletters? Do they mint a subscription token that we gate with a Graph rule? Or are subscriptions managed through a custom graph? And are emails stored in Grove? @lens/defispartan @lens/stani @lens/mp