I need an iOS app built in Swift/SwiftUI that lets students take full-length practice exams for every AP subject. I will supply all questions and scoring keys later, so your focus is the framework: a clean exam engine, user registration with email + password, and a subscription paywall offering monthly and annual plans through Apple in-app purchases. A new user should be able to create an account, choose a plan, and immediately see a catalog of AP exams. Selecting an exam loads sections sequentially with a timer, navigation between questions, auto-save, and a results screen that shows raw score and percentage. Progress needs to sync across devices. Please wire the content layer to a simple, secure backend (Firebase, Supabase, or another you prefer) where I can upload or update exams without a new build—JSON or CSV import is fine. The code must follow App Store guidelines for auto-renewable subscriptions, including restore purchases, graceful expiry handling, and localized pricing. Deliverables • Xcode project ready for App Store submission • Backend setup script or guide for uploading exam files • Brief README covering build, deployment, and how to add new exams • One test AP exam pre-loaded so I can verify the flow Acceptance is complete when I can sign in on a fresh device, purchase a subscription, download the sample exam, finish it, and see the score retained after relaunch. Useers must also be able to track their progress and scores on the app. with a graph showing progress and "streak days". Also, add in an AI model that will be able to generate quizzes based on a user prompt for that specific topic in the subjects.