What happens after you blow up your entire life to be with the person you love? The second season of “Starstruck” explores the question that rom-coms generally leave unanswered after their happy endings, wisely acknowledging that a big romantic gesture doesn’t erase all the obstacles present between two people getting — and staying — together. On its surface, the British import on HBO Max seems like a standard wish-fulfillment fantasy à la “Notting Hill”: a “normie” finds unlikely romance with a star.