Parse SSE `status` events alongside `chunk` events and display the
status text next to the spinner while the assistant is generating.
Previously the Android app discarded all non-chunk SSE events.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Timer.periodic every 60s calls silentRefresh() on BriefingNotifier.
silentRefresh() patches AsyncData directly — never triggers AsyncLoading —
so existing content stays on screen while the fetch is in flight.
WidgetsBindingObserver pauses polling when app is backgrounded.
Polling is also skipped while a reply is actively streaming.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Migrate StateNotifierProvider/StateNotifier → NotifierProvider/Notifier,
StateProvider → NotifierProvider with simple notifier, FamilyAsyncNotifier
removed in Riverpod 3 (replaced with constructor-arg pattern), and rename
.valueOrNull → .value throughout all providers and screens.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>