Feature request: Soroban Cahoots from Trezor

[elkimek]

With Soroban Cahoots and Whirlpool to xpub implemented all is missing is to spend privately from HWW.

According to @prusnak Trezor is ready to do that. I can't provide more information on what would it take personally, but I'm sure he would gladly advise on that.

Thanks! :)

[prusnak]

More technical info about Trezor:

• Trezor can sign external inputs via InputScriptType.EXTERNAL
• each external input has to be accompanied by Ownership Proof defined in SLIP-0019
• even more details are in the PR that added External inputs to Trezor: Support external inputs trezor/trezor-firmware#1080

[craigraw]

Sparrow uses HWI to communicate with Trezor, so it appears that progress will need to be made on bitcoin-core/HWI#551 to support this.

[elkimek]

Seems it's on the right path :) bitcoin-core/HWI#590