nrobi144
22e50cc852
perf(feed): viewport-aware metadata loading with batched author filter
Two optimizations for feed metadata loading speed:
1. Batched author filter (FeedMetadataCoordinator.loadMetadataBatched):
Single Filter(kind:0, authors:[all visible]) instead of individual
per-pubkey subscriptions through rate limiter. Closes after EOSE.
Follows ChessRelayFetchHelper one-shot pattern. Max 100 authors/filter.
2. Viewport-aware scroll observation (FeedScreen):
snapshotFlow reads LazyListState.visibleItemsInfo (zero recomposition)
with 500ms debounce + distinctUntilChanged. Only fetches metadata for
visible notes ± 10 item buffer. Initial load batches first 30 notes.
Before: 100+ authors × 20/sec rate limit × 7 relays = 5+ seconds
After: ~20 visible authors × 1 batched sub × 7 relays = <1 second
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>