LiveActivitiesChannel.notes is mixed-kind (chat, zaps, raids, clips, presence),
and chat dominates by volume in active rooms. The Nests feed filter scanned it
twice per room per recompute -- once for any-fresh-presence, once for fresh
on-stage presence -- doing an `is MeetingRoomPresenceEvent` cast on every chat
message just to find the speakers.
Add a presenceNotes index on LiveActivitiesChannel keyed by author pubkey
(presence is replaceable per author, so the key auto-collapses heartbeats).
Populate it from LocalCache.consume(MeetingRoomPresenceEvent). Switch
NestsFeedFilter to a single hasFreshSpeakers() pass over the index, dropping
the now-redundant isLiveByPresence() check (hasFreshSpeakers implies it).
Migrate NestsFeedLoaded's latest-presence flow to the same index.
Claude
d87fc36d21