Interest in integration with OnlyKey

Hi,

We have a complimentary product OnlyKey that would allow users to keep their keys offline in a token. This allows doing private key operations without the private key needing to be exposed on the system. This is a recently introduced feature and now we are looking to integrate with PGP solutions like the Keybase desktop app. Essentially, this would be a minor edit for the app to support OnlyKey. The user could select to do private key operations via the key stored on OnlyKey and then the request is sent via USB HID so it is universally supported on Windows, Mac, Linux, Android. Lets talk if your interested. [Here is video that demonstrates the feature](https://vimeo.com/210800252)

Begin with the proposed OnlyKey integration and the linked demonstration video; no repository file, test, or entry point is identified. Clarify the supported Keybase clients, USB HID protocol, and acceptance criteria before implementation; done would be an agreed scope and a validated integration plan.

Written by the indexing model from the issue text.