Cross-Platform Expense & Attendance App

I want to replicate the core functionality of Odoo HR’s expense and attendance modules (see https://apps.odoo.com/apps/modules/19.0/odoo_hr) in a dedicated mobile app that runs smoothly on both iOS and Android.

The build should include two tightly-integrated sections:

• Expense tracking with receipt upload (photo or PDF), category tagging, and an approval workflow that lets managers accept, reject, or comment on each claim.
• Attendance management covering real-time employee check-in/check-out, leave requests and balances, and automatic overtime tracking.

A clean, modern UI is essential, and the data must sync reliably to a secure backend so records stay consistent across devices. You’re free to use any robust cross-platform stack—Flutter, React Native, or a comparable toolset—as long as the finished APK and IPA perform natively and pass store reviews.

On hand-over I’ll need:
1. Source code with installation notes
2. Compiled builds for both platforms
3. Basic setup documentation for the backend you choose

If you’ve delivered similar HR or finance apps before, I’d love to see a quick demo or screenshots alongside your proposal.