Protocol Fee Expansion: Arc

This proposal is part of the protocol fee rollout, following proposals #93, #94, #95, #96, #99, and #100. It uses the expedited governance process approved in UNIfication, where fee parameter update proposals can bypass the RFC stage and go directly to a five-day Snapshot followed by an onchain vote.

Since protocol fees went live on Ethereum mainnet in late December last year, the rollout has extende