Mobile Employee Schedule With Time Tracking

I need a mobile-first work-schedule application designed solely for our employees. The single, non-negotiable feature is rock-solid time tracking: staff must be able to clock-in, clock-out, record breaks, and review their own daily totals from any modern iOS or Android device. Shift planning and push notifications are not required in this phase, but the architecture should leave room for those additions later.

For this initial release, please deliver:
• A clean, intuitive mobile interface (native Swift/Kotlin or a cross-platform stack such as Flutter or React Native is fine)
• Secure user authentication tied to our existing employee IDs
• Real-time clock-in/out with local offline support and automatic sync once connectivity returns
• A lightweight back-end (Firebase, Supabase, or a simple REST API with PostgreSQL) storing punch data and producing daily time summaries
• Basic export of individual timesheets to CSV or JSON for payroll import

Acceptance criteria: employees can download the app, sign in, record time, review totals, and export their own report without administrator intervention. Provide source code, build instructions, and a brief hand-off video or document so our internal IT can deploy updates.