Restructure the loans screen around Earn/Borrow tabs and add the supply/withdraw entry points behind them.
- add summary card with supplied, borrowing, HF and borrow limit
- split content into Earn and Borrow tabs with their own asset lists
- add supply and loan-withdraw screens with a shared asset selector
- add loan-action-completed receipt screen for both actions
- register the new routes in the root stack
Co-Authored-By: Claude Opus 5 (1M context) noreply@anthropic.com