fix(sessions): centralize global polling

packages/ui/src/hooks/useGlobalSessionsPolling.ts

@@ -0,0 +1,34 @@
+import React from 'react';
+import { getAllSyncSessions } from '@/sync/sync-refs';
+import {
+  ensureGlobalSessionsLoaded,
+  refreshGlobalSessions,
+} from '@/stores/useGlobalSessionsStore';
+
+export const GLOBAL_SESSIONS_REFRESH_INTERVAL_MS = 45_000;
+
+type ScheduleInterval = (callback: () => void, delay: number) => number;
+type ClearInterval = (intervalId: number) => void;
+
+export const startGlobalSessionsPolling = (
+  initialLoad: () => void,
+  refresh: () => void,
+  scheduleInterval: ScheduleInterval = window.setInterval.bind(window),
+  clearScheduledInterval: ClearInterval = window.clearInterval.bind(window),
+): (() => void) => {
+  initialLoad();
+  const intervalId = scheduleInterval(refresh, GLOBAL_SESSIONS_REFRESH_INTERVAL_MS);
+  return () => clearScheduledInterval(intervalId);
+};
+
+/** Owns the one global-session polling lifecycle for the main app runtime. */
+export const useGlobalSessionsPolling = (enabled: boolean): void => {
+  React.useEffect(() => {
+    if (!enabled) return;
+
+    return startGlobalSessionsPolling(
+      () => { void ensureGlobalSessionsLoaded(getAllSyncSessions()); },
+      () => { void refreshGlobalSessions(); },
+    );
+  }, [enabled]);
+};