* feat: add multicall routing strategy
* Updated proxyd config to accept a routing strategy parameter
* Added multicall routing strategies
* Refactored backendGroup.Forward to handle multiple types of routing strategies
* Background.ForwardToBackend now will return results via a channel
- Return early on network errors or invalid responses within updateBackend (e.g., zero block height)
- Prevent premature node banning
- Use existing sliding windows for node banning for unexpected tags or excessive network errors
