Frontend:
- P0: Replace constant estimateSize(40px) with content-based estimation
using line count and reply presence for accurate virtual list scroll
- P1: Replace Shadow DOM custom elements with styled spans for @mentions,
eliminating expensive attachShadow calls per mention instance
- P1: Remove per-message ResizeObserver (one per bubble), replace with
static inline toolbar layout to avoid observer overhead
- P2: Fix WS token re-fetch on every room switch by preserving token
across navigation and not clearing activeRoomIdRef on cleanup
Backend:
- P1: Fix reaction check+insert race condition by moving into transaction
instead of separate query + on-conflict insert
- P2: Fix N+1 queries in get_mention_notifications with batch fetch
for users and rooms using IN clauses
- P2: Update room_last_activity in broadcast_stream_chunk to prevent
idle room cleanup during active AI streaming
- P3: Use enum comparison instead of to_string() in room_member_leave
Backend:
- Atomic seq assignment via Redis Lua script: INCR + GET run atomically
inside a Lua script, preventing duplicate seqs under concurrent requests.
DB reconciliation only triggers on cross-server handoff (rare path).
- Broadcast channel capacity: 10,000 → 100,000 to prevent message drops
under high-throughput rooms.
Frontend:
- Optimistic sendMessage: adds message to UI immediately (marked
isOptimistic=true) so user sees it instantly. Replaces with
server-confirmed message on success, marks as isOptimisticError on
failure. Fire-and-forget to IndexedDB for persistence.
- Seq-based dedup in onRoomMessage: replaces optimistic message by
matching seq, preventing duplicates when WS arrives before REST confirm.
- Reconnect jitter: replaced deterministic backoff with full jitter
(random within backoff window), preventing thundering herd on server
restart.
- Visual WS status dot in room header: green=connected, amber
(pulsing)=connecting, red=error/disconnected.
- isPending check extended to cover both old 'temp-' prefix and new
isOptimistic flag, showing 'Sending...' / 'Failed' badges.
