Also renames fields `IsLastInSpan` to `Safe` because that's semantically
clearer. That a last batch in a span batch is pre-Holocene the indicator
for a safe block promotion is an implementation detail. It's better to
name the effect rather than the reason.

* op-node/rollup: Implement Holocene invalid payload handling

* op-node: update comment about block-processing errors

---------
Co-authored-by: protolambda <proto@protolambda.com>

* op-node: sequencer / engine events refactor

incl sequencer events fixes

* op-node: distinguish block sealing error kinds

* op-node: review fixes, stashed tweaks

* op-node: events based sequencer chaos test

* op-node: fix missing DerivedFrom data in attributes test

* op-node: drop old wip debugging work log

* op-node: sequencer move OnEvent function

* op-node: update stale todo comment

* op-node: detect derivation block-building as sequencer, and avoid conflict

* op-node: clarify comments and rename PayloadSealTemporaryErrorEvent to PayloadSealExpiredErrorEvent to describe applicability better

* op-node: prevent temporary engine error from influencing inactive sequencer

* op-node: event-system with tracing

* op-node: fix global synchronous events queue execution

* op-node: bump rate limits on action tests

* op-node: add missing read-lock to synchronous event executor

* op-node: automatically attach emitters to derivers that need one

* op-node: fix driver step hot loop, improvement events and add utils

* op-node: fix verifier event processing liveness

* op-node: add events_rate_limited metric

* op-node: bump events rate limits

* op-node: event handling on block attributes

todo

* op-node: update plasma step to no longer hardcode pipeline stepping