feat(admin): reorganize housekeeping and strengthen shared workflows

src/hooks/use-visible-polling.ts

@@ -0,0 +1,38 @@
+"use client";
+import { useEffect, useRef } from "react";
+/** Refresh after the prior request settles; pause while the tab is hidden. */
+export function useVisiblePolling(
+	refresh: () => Promise<unknown>,
+	delay: number,
+) {
+	const callback = useRef(refresh);
+	callback.current = refresh;
+	useEffect(() => {
+		let stopped = false,
+			running = false;
+		let timer: ReturnType<typeof setTimeout> | undefined;
+		async function tick() {
+			if (stopped || running) return;
+			clearTimeout(timer);
+			if (document.visibilityState === "hidden") return;
+			running = true;
+			try {
+				await callback.current();
+			} finally {
+				running = false;
+				if (!stopped) timer = setTimeout(tick, delay);
+			}
+		}
+		function visibility() {
+			if (document.visibilityState === "visible") void tick();
+			else clearTimeout(timer);
+		}
+		void tick();
+		document.addEventListener("visibilitychange", visibility);
+		return () => {
+			stopped = true;
+			clearTimeout(timer);
+			document.removeEventListener("visibilitychange", visibility);
+		};
+	}, [delay]);
+}