ContextSummarizedEvent (registered) keyed on stable session sequence, not the
ephemeral pack ordinal, so replay reuses the recorded summary artifact and never
re-calls the LLM (invariants #6/#8). TierContextSummarizer mirrors
JournalCompactionService for freeform context (tool outputs/docs/retrieved text)
the journal path doesn't cover. ContextState + DefaultContextReducer fold the
event; reducer replay-safety unit-tested.
kami
e0c222392c