HomeView: setInterval every 90s refreshes events, orphan tasks/notes,
and hero next-up task. Never touches loading ref, so the page content
stays stable — only the data silently swaps when the fetch completes.
Skips when document.hidden or initial load is still in progress.
BriefingView: setInterval every 60s refetches today's messages, but
only when viewing today's conversation and not currently streaming.
Compares message count and last message content before updating to
avoid unnecessary re-renders.
Both timers are cleared on unmount.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
bvandeusen
08d738ddfb