fix: improve scheduling code

src/ui/hooks/use-idle-derived.ts

@@ -0,0 +1,23 @@
+import { derived, type Readable } from "svelte/store";
+
+import { createBackgroundBatchScheduler } from "../../util/scheduler";
+
+export function useIdleDerived<T>(props: {
+  batch: Readable<Array<() => T>>;
+  timeRemainingLowerLimit: number;
+  initial: T[];
+}) {
+  const { batch, timeRemainingLowerLimit, initial } = props;
+
+  const scheduler = createBackgroundBatchScheduler<T>({
+    timeRemainingLowerLimit,
+  });
+
+  return derived(
+    batch,
+    ($batch, set) => {
+      scheduler.enqueueTasks($batch, set);
+    },
+    initial,
+  );
+}