Finish Building a Mobile App (Wearable Integration, Calendar Sync, New Features, Payments)

I have an existing mobile app originally called Cognisia, which now needs to be rebranded and further developed into Clairvue. The app is primarily a health & wellness / cognitive training app that already has a working base but needs several enhancements and integrations.

To Do:

App Rebranding

Change app name, branding, and UI elements from Cognisia → Clairvue.

Update app icon, splash screen, and relevant assets.

Wearable Integration

Integrate APIs from Fitbit, Apple Watch, and/or Google Fit for activity, heart rate, and sleep tracking.

Ensure data is displayed meaningfully in-app (progress dashboards, reports, etc.).

Calendar Sync

Sync exercises and reminders with device calendars (Google Calendar, iCal, Outlook if possible).

Add notification/reminder functionality.

Add More Exercises & Content

Implement new cognitive/mental wellness exercises into the app.

Ensure content structure is scalable and easy to update in the future.

Payment System

Implement secure subscription/paywall functionality (e.g., Stripe, PayPal, Apple Pay, Google Pay).

Support free trial + recurring subscription model.

Testing & Deployment

Cross-platform testing (iOS + Android).

Final deployment to App Store & Google Play.