Merge bug/scheduler-progress-visibility: live progress for any scheduler job + parallel RSS polling

frontend/src/lib/useLiveQuery.ts

@@ -8,14 +8,22 @@ import { useQuery, type QueryKey } from "@tanstack/react-query";
 export function useLiveQuery<T>(
   key: QueryKey,
   queryFn: () => Promise<T>,
-  opts: { intervalMs?: number; enabled?: boolean } = {}
+  // intervalMs may be a function of the latest data, so the poll cadence can adapt to it
+  // (e.g. poll faster while a job is running). react-query re-evaluates it after each fetch
+  // against fresh data — the right place for this, vs. a React state toggle that can lag or
+  // stall the live updates.
+  opts: { intervalMs?: number | ((data: T | undefined) => number); enabled?: boolean } = {}
 ) {
   const { intervalMs = 4000, enabled = true } = opts;
   return useQuery({
     queryKey: key,
     queryFn,
     enabled,
-    refetchInterval: enabled ? intervalMs : false,
+    refetchInterval: !enabled
+      ? false
+      : typeof intervalMs === "function"
+        ? (query) => intervalMs(query.state.data as T | undefined)
+        : intervalMs,
     refetchIntervalInBackground: false,
     staleTime: 0,
   });