***Project Description: Google Play Books–Style Ebook App (React Native + FastAPI) Build a mobile ebook app inspired by Google Play Books, using React Native (Expo) for the frontend and FastAPI (Python) for the backend mock API. Users can search books by language and keyword, download them for offline reading, and open them in a built-in reader (EPUB/PDF). No login or external authentication is required. ***Technical Requirements Frontend: React Native (Expo) Backend: FastAPI (Python, mock JSON API) Platforms: iOS + Android Environment: Must run entirely local (FastAPI + Expo) No external APIs, no third-party authentication *** Authentication No login or signup features. When user identification is needed (favorites, reading progress), use the device’s UUID as a unique identifier. Generate it locally on first launch (e.g. SecureStore or AsyncStorage). No personal data collection or online accounts. *** Core Features All features must be fully functional using mock JSON data served by FastAPI. Do not deliver static UI-only mockups. ***Screen Description Home / Discover Displays featured and new books by language (same layout style as Google Play Books). Search Language selector + free-text search bar for keywords. Book Detail Shows title, author, description, language, and cover image. Includes “Download” and “Add to Favorites” buttons. Library / Favorites Locally stored list of downloaded or favorited books. Reader Built-in EPUB/PDF reader with pagination, font size toggle, dark mode, and reading progress memory. *** Backend (FastAPI Mock API) Implement endpoints returning realistic JSON responses: GET /api/books?language=ja&query=python → list of matching books GET /api/book/[slug] → book detail (title, author, description, file URLs) GET /api/download/[slug] → download link (mock URL) POST /api/favorites → save book by device_uuid GET /api/favorites?uuid=[device_uuid] → get user's saved books Mock data must look realistic (titles, author names, language tags, thumbnails). No database needed; in-memory or static JSON is acceptable. *** Deliverables Complete source code (React Native + FastAPI) Local run instructions (npm start, uvicorn main:app --reload) Clean, modular structure ready for real API integration ***Goal Deliver a Google Play Books–style mobile app with offline reading capability, searchable multilingual book catalog, and fully functional mock API — all running locally, no login required.