In this commit we add the version 3 htlc, which is implemented with
taproot script spending the two payment paths: the claim path case, and
the timeout case.
Formatting our error was stifling any grpc error returned by the
server. Instead, we bubble up our grpc error, setting an unknown
code if the server did not specifically return an error code.
To allow users to specify differing confirmation targets, we store the
swap conf target per-swap. This makes us restart safe, so we do not
forget confirmation values for swaps that are in flight when we restart.
Once we have revealed our preimage to the world with a sweep attempt,
we can safely push our preimage to the server to speed up on chain
claim.
Rather than rely on the server, we use the state of our invoice in lnd
to determine whether we should continue trying to push the preimage to
the server.
Allow user to specify that htlc will be published by an external source.
In that case no internal htlc tx will be published.
To facilitate sending to the htlc address, the swap initiation response
is extended with that address.
This commit adds the required code to persist loop in swaps. It also
introduces the file loop.go to which shared code is moved.
Sharing of contract serialization/deserialization code has been
reverted. The prepay fields do not apply to loop in, but were part of
the shared contract struct. Without also adding a migration, it wouldn't
be possible to keep the shared code.
In general it is probably more flexible to keep the contract
serialization code separated between in and out swaps.
