- Add AppSender interface to engine/core for VM plugin communication
- Add AppHandler interface with message handling methods
- Add Fx struct for feature extensions
- Add AppSender interface to engine/chain/block for node integration
- Fix GetValidatorState to return typed ValidatorState instead of interface{}
- Add appsender package in core for consensus-level app messaging
These interfaces are required by the EVM package to build successfully
with the consensus package.
zeekay
7febfe80c5