Prop 105: Pleiades Upgrade - Phase II

This proposal will upgrade the chain to Pleiades Phase II, the second in a series of security upgrades for Gravity Bridge
This update includes three major changes.

1. Invariants are now run by default every 17-199 blocks. This ensures the chain will automatically halt in less than an hour in the case that any invariant is violated. You may override this default period with a longer one if your node can not sustain the required disk i/o to run invariants so often.
2. The full store check invariant reads all Gravity Bridge related data from the store, cross referencing and verifying it. This is designed to directly counter store corruption, usually a precursor to some sort of double spend attack, by detecting them automatically and combined with (1) halting the chain so validators can coordinate a return to safe operation.
3. As required in Gravity Bridge governance proposal #86 this update provides a governance controlled fee parameter, initialized to two basis points for withdraws. Due to limitations in Keplr preventing many tokens from being used as fee tokens the main SendToEth message has been modified and will require a quick update by frontend integrators to include the new fee field.
4. To determine ETH2 finality currently GBT waits a constant 96 blocks, this has been changed to query the latest finalized block, this should increase the finality speed by 7 minutes or so on average.