keyboard property
What the peer's keyboard has been CONFIRMED to guarantee (RFC 0020
ยง11). Optional keyboard=<bits> INIT param.
Null when the peer declares nothing, which reads as press-only. A peer's lifecycle support is never
inferred from protocolVersion: version says the codecs match, not
that the terminal on the far end honoured flag 8. A fleury shell
relay in front of Ghostty and one in front of Terminal.app speak the
identical wire version and have completely different keyboards.
Implementation
final KeyboardCapabilities? keyboard;