Archive key material on wallet closure

[lukasz-zimnoch]

Wallet operators should listen to Bridge's WalletClosed events and perform necessary operations upon wallet closure. The most important thing is archiving the key material so the given wallet is no longer considered active by the operator's node. This is important in the context of the new RFC 12 coordination mechanism as closed wallets' operators should not waste network bandwidth for coordination messages.

Tasks

Beta Give feedback

1. Archive key material on wallet closure #3814
   📟 client +1