Connect FX_CHECKER to Market Data

The core converter now works from fallback values. This module connects the project to its external data sources and turns the Rates view into a useful market-data screen.

What you will build

• the searchable Rates table
• the live exchange-rate request
• fallback behavior and connection status
• cross-view interactions between Rates, Popular Currencies, and Convert

Checkpoint

The application should use live rates when the service is available and continue to work with fallback values when it is not.

Next, we will persist the user data that belongs to the Favorites and History views.