Add Base (Coinbase) Wallet Support

## Description

Add support for Coinbase Wallet deep linking on mobile platforms (Android and iOS).

Coinbase Wallet is already part of the auth flow options, but the mobile app needs to properly handle the `cbwallet://` URL scheme to open the Coinbase Wallet app when users select it during WalletConnect authentication.

## Acceptance Criteria
- [ ] Android: Ensure `cbwallet://` scheme is handled in WebView's `shouldOverrideUrlLoading()`
- [ ] iOS: Verify ASWebAuthenticationSession properly handles Coinbase Wallet redirects
- [ ] Test WalletConnect flow with Coinbase Wallet on both platforms

## Related
This builds on top of the general deep link handling improvements in #1095.