Description
Implement a dedicated notifications screen to track account activity, price alerts, and major news events. Complexity: Medium (150 points) 🔔

Requirements and Context

• A new screen reachable via a bell icon in the header.
• List items should be "Read" or "Unread".

Success Criteria (Done)

• NotificationsScreen fetching from GET /notifications.
• Mark as read functionality (tap or button).
• Empty state message when no notifications exist.

Suggested Execution

• Branch: feat/mobile-notifications-ui
• Implementation: Use a persistent badge count on the bell icon.

Test and Commit

• Testing: Trigger a test notification and verify it appears in the list.
• Example Commit Message: feat(mobile): implement in-app notification center
• Screenshots: Include a screenshot of the notifications list.