Persist CFD state to enable collab close on the maker

[da-kami]

The maker has to be able to accept a collaborative close by a taker.

@bonomat @luckysori it would be great if you could outline what is the minimal information to be persisted on the maker side so that the custom output can be removed when a taker requests it.

[luckysori]

it would be great if you could outline what is the minimal information to be persisted on the maker side so that the custom output can be removed when a taker requests it.

I think the minimal information is actually null. We cut some corners when implementing the remove_custom_output protocol, so the maker will just accept anything automatically on the rust-lightning layer.

The taker will need to provide:

• maker_pubkey.
• custom_output_id.
• settlement_amount_taker_msat.
• settlement_amount_maker_msat.

[da-kami]

Sweet! We can keep this ticket low-prio until after the tournament then!