The signing set should be the first group to submit preprocesses to Tributary.
Re-attempts shouldn't be once every 30s, yet n blocks since the last relevant
message.
Removes the use of an async task/channel in the signer (and Substrate signer).
Also removes the need to be able to get the time from a coin's block, which was
a fragile system marked with a TODO already.
Writes a custom unsigned extrinic creator due to subxt having an internal error
with the scale metadata. While the code in our scope increased, it's much more
ergonomic to our usage. We may end up rewriting most of subxt, eventually.
Step moved a step forward after an externally synced/added block. This created
a race condition to add the block between the sync process and the Tendermint
machine. Now that the block routes through Tendermint, there is no such race
condition.
Previously, Tendermint needed to be live more than it needed to be correct.
Under the original intention for it, correctness would fail if any coin
desynced, which would cause the node to fail entirely. By accepting a
supermajority's view of state, despite its own, a single coin's failure would
only lead to inability to participate with that single coin.
Now that Tendermint is solely for Tributary, nodes should halt a coin-specific
chain if their view of the chain differs. They are unable to meaningless
participate regardless.
This also means a supermajority of validators can no longer fake messages from
other validators, allowing the Tributary chain to use uniform weights with much
less impact. There is still enough impact they can't be used (ability to cause
a fork), yet they should allow uniform block production (as that's solely a DoS
concern).
While we prior could've simply additionally checked signatures, add_block's
lack of a failure case would've meant it had to panic. This would've been a DoS
possible a minority-weight *which affected the entire coordinator* and
therefore *the entire validator for all coins*.
While Bitcoin practically doesn't have long re-orgs, it is possible for a
single miner to build a long chain. Recently, a miner found 5 blocks in a row,
which would be enough to re-org a transaction Serai considered finalized.
