Pedometer App with Firebase Sync

I’m looking for a straightforward, no-frills way to capture step counts on both iOS and Android and push them to Firebase in real time. There’s no login flow—just launch, count, and sync.

Core needs
• Use the phone’s built-in pedometer / motion sensor to track steps continuously.
• Display today’s total on a minimalist screen.
• Write every change immediately to Firebase (Firestore or Realtime Database—whichever you prefer) and merge any offline data once the device reconnects.
• Keep the codebase shared—Flutter, React Native, or another cross-platform stack that can ship to both stores without duplicating effort.

Deliverables
• Clean, well-commented source code.
• Basic README explaining setup, Firebase configuration, and how to run the project on each platform.
• Short test plan or demo video proving real-time syncing works.

This is meant to be a simple proof-of-concept, so focus on reliability and clear code over polished UI.