I need a complete Android mobile application focused on boosting productivity. The core work includes designing an intuitive user interface, coding stable and efficient functionality, and packaging the finished APK for release on Google Play. To keep things straightforward, here are the concrete deliverables: • Interactive UI/UX mock-ups approved before coding • Fully functional Android app (latest SDK, Kotlin or Java) • Clean, well-documented source code in a shared repository • Basic testing report confirming smooth operation on standard devices I will supply any brand assets or content once we begin. Please outline the development timeline, preferred tech stack, and a short note on how you ensure performance and data security when you reply so I can move fast on awarding the project.