QR code connection should extract Avalanche X/P key for full chain support

[MoonBoi9001]

The QR code connection only extracts the EVM key, ignoring the Avalanche X/P key even when present.

Problem: Keystone 3 Pro's QR contains both keys:

• 44'/60'/0' (EVM)
• 44'/9000'/0' (Avalanche X/P)

But KeystoneQRConnector.tsx only takes the first:

const [key] = cryptoMultiAccounts.getKeys();

Result: QR-connected wallets lose P/X chain functionality, forcing USB connection which defeats air-gap security.

Fix: Extract all keys and include Avalanche key when present.