Fix Background Step Counting

I built a cross-platform health and fitness app with Expo + React Native. Everything works fine except one critical piece: step counts stop the moment the user closes the app or locks the screen.

Current stack & set-up
• Runs on both Android and iOS.
• Uses the built-in Pedometer API.
• Background execution is wired through Expo Task Manager, but the task never fires once the app goes to the background.

What I need
A clean, production-ready solution that keeps counting steps continuously—whether the app is in the foreground, background, or fully terminated—without draining the battery or breaking App Store / Play Store guidelines.

Acceptance checklist
• Reliable step data persists across app restarts and device reboots.
• Works on recent Android and iOS versions (including doze / low-power modes).
• Code is commented and any native modules or permissions are clearly documented so I can reproduce the build.

Deliver the updated source, plus any configuration notes, and I’ll take it from there.

Disclaimer: Project is highly confidential, therefore, the legal rules will be applied.