Payment URI with fallback #284
Description
Some payment requests contain an on-chain fallback address. This makes these payment requests compatible with (old) main-chain wallets and Lightning wallets. The user can then choose how they want to pay or switch to on-chain if Lightning fails.
The address format looks like this:
bitcoin:bc1xxxxx?lightning=lnurl1xxxxx
I think it makes sense to introduce this for Liquid addresses as well, so that users can choose whether they want to pay via the main-chain or Liquid.
The address format could look like this:
bitcoin:bc1xxxxx?lightning=lnurl1xxxxx&liquid=Glxxxxx
It would make sense to ask users when creating invoices whether they want to embed main chain, liquid, or both in the payment request.
Somewhat related: #81