Audit-driven fixes for the audio-room reactions overlay:
1. RoomReactionsAggregator now dedups by event id. The previous code
appended every event to a flat list, but LocalCache.observeEvents
re-emits the full matching list on every cache mutation — so an
N-reaction window grew quadratically and the overlay rendered the
same emoji once per replay. Keyed by event id collapses re-emits.
2. RoomPresenceAggregator gains applyOrNull that returns null when an
incoming heartbeat is older-or-equal to the cached presence; the VM
skips the StateFlow write in that case. In a 200-peer room, every
replay used to copy a 200-entry map plus run an O(N) StateFlow
equality check 200 times per emission. Now it's one-and-skip.
3. ReactionsEvictionTicker only ticks while the aggregator is non-empty.
Once the last reaction expires the loop self-cancels until the next
reaction lands — a quiet room costs no scheduled work.
4. REACTION_WINDOW_SEC dropped 30s -> 10s. Reactions are about what
the speaker is saying right now; a 10s window keeps the overlay
timely instead of bleeding into the next paragraph.
5. SpeakerReactionOverlay drives a per-chip lifecycle animation: each
chip drifts upward ~16dp and fades over the 10s window. A fresh
reaction (same emoji) restarts the chip's animation. The
AnimatedVisibility outer entry/exit still smooths first-arrival and
final disappearance.
Tests: added a re-emit dedup case to RoomReactionsStateTest plus an
end-to-end replay assertion in NestViewModelTest. Existing tests
updated to use unique event ids.
https://claude.ai/code/session_01DMeCvWyBYVVVPez2hwqCs4
Claude
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