:broom: x2

Mark's nits pt. 1

Buffer `FetchUnsafeBlock` channel

Bump channel size

Don't rely on P2P to detect the gap; Test WIP

Resolve conflicts

Fix test

:broom:, fix `op-node` PayloadQueue test after dedup change

:broom:

Don't hardcode sequencer RPC port

:broom: `SystemConfig` hooks

Attempt CI fix

Force e2e setup to loop through nodes in alphabetical order

Temp: Add Kelvin's CI fix