Payments and integrations

QuickSkill's product-side payments use RevenueCat for native in-app purchases, with server-side receipt verification in api/. This is separate from the one-time Stripe checkout you used to buy QuickSkill through this portal — that Stripe integration lives in the portal, not in your delivered repository.

Other integrations documented per-provider in your repository's .env.example files: email (Resend, optional in dev), AI provider keys, and optional Upstash/Expo access tokens. Treat every key as required-in-production, optional-in-dev unless the .env.example comment says otherwise.