0-conf txs with dependent txs in wallet

[antiochp]

This is a bit of a weird edge case and needs thinking through. Putting it here so we don't forget.

It is possible to "spend" an unconfirmed output in the wallet via --min_conf 0.

And it is possible that an output will 0 confirmations will never confirm.
One scenario is the sender never finalizes the tx, for example.

A tx "spending" this unconfirmed output will not (and cannot) be accepted in the mempool.
So we can build a valid tx in wallet that never reaches the local mempool and will never confirm.
The wallet is not aware of this and will simply show the tx (and associated outputs) as unconfirmed.

grin-wallet info shows funds as "Awaiting Finalization" which is misleading. The tx may have been successfully finalized, just not successfully accepted to the mempool.

[cliik]

This is interesting. Would it make sense to automatically move a transaction to the "unconfirmed" state, when the wallet finalizes a transaction? This ofc would only work for the sender wallet (in SRS flow) that finalizes the tx, unless we introduced another communication round to the receiver 😬