- useInfiniteStream: wrap fetchNextPage and refresh in useCallback so
InfiniteScrollArea's IntersectionObserver does not re-subscribe on
every parent render.
- InfiniteScrollArea: do not render 'End of stream' until at least one
item has loaded and the initial query has settled (was flashing on
mount before first fetch).
- AgentHealth: pass isLoading + hasItems to both InfiniteScrollArea
wrappers.
Scrollable container with top/bottom IntersectionObserver sentinels.
Fires onTopVisibilityChange when the top is fully in view and
onEndReached when the bottom is within 100px. Used by infinite log
and event streams.
