I need a lightweight Android app (Java or Kotlin) that exposes a clean, well-documented REST/JSON API for a full AEPS workflow. The first release must cover: • Core AEPS services: cash-withdrawal, balance enquiry, mini statement generation and daily AEPS settlement. • Cash-withdrawal extras: biometric authentication through RD-compatible devices, fallback OTP verification, and reliable transaction-history tracking (local cache + remote sync). The API layer should be modular so I can plug in other rails (DMT or BBPS) later without breaking existing endpoints. Please keep dependencies slim, follow Android X guidelines and use Retrofit, Room or equivalent open-source libraries—no vendor lock-in. Acceptance will be based on: 1. End-to-end demo on any Android 9+ handset showing each AEPS call succeeding against the test environment. 2. Postman collection and Swagger/OpenAPI file that mirror every implemented endpoint. 3. Clear README covering build steps, device permissions, RD service pairing and settlement cron. Once the above is stable, I’ll handle Play-Store polish myself; your focus is tight, robust AEPS functionality delivered as a reusable module.