feat: add legacy support for yoroi-frontend public key QR codes
Add parser for legacy yoroi-frontend QR code format that exports publicKeyHex as JSON. When scanned with the in-app scanner, these legacy QR codes are now interpreted as read-only wallet restoration, same as the newer web+cardano:// format. The parser extracts accountVisual from the derivation path array if present, ensuring proper restoration for wallets with multiple accounts.