keystone QR format compatibility

[shrpne]

Hey guys, thank you for the great software!

What do you think about adding compatibility with Keystone QR code format, so more wallets can use airgap-vault? For example, OKX wallet only supports Keystone, but not Airgap

[ChainCoderX]

good requirement.

[Sylla88]

hope they can pair up

[zhorsex]

建议增加对Keystone QR码格式的兼容性，这将有助于airgap-vault支持更多钱包，提升用户体验。