ReadonlyentriesReadonlyheldUser messages waiting for a promptConsume.
Optional ReadonlyoriginConversation this feed continues (fork); its prompt up to origin.event precedes entries.
ReadonlypositionEvents folded so far, which is the feed position of the next one.
ReadonlypositionsFeed position of every folded event, to resolve a from.event; persistent, since a copy per event is quadratic.
ReadonlystaleThreads and turns that merged into a parent holding entries they never saw, with those entries' source events. The merge still happens; whether to accept, re-run or correct is the harness's call.
Readonlythreads
The main thread's prompt; only appended to, except by
compact.