Improve media cleanup performance with bounded concurrency and aggregated failure reporting

lib/async-pool.ts

@@ -0,0 +1,29 @@
+/**
+ * Execute async work with a bounded number of in-flight tasks.
+ */
+export async function runWithConcurrency<T>(
+  items: T[],
+  limit: number,
+  worker: (item: T) => Promise<void>
+): Promise<void> {
+  if (items.length === 0) return;
+
+  const concurrency = Math.max(1, Math.floor(limit));
+  let nextIndex = 0;
+
+  async function runWorker(): Promise<void> {
+    while (true) {
+      const currentIndex = nextIndex;
+      nextIndex += 1;
+
+      if (currentIndex >= items.length) {
+        return;
+      }
+
+      await worker(items[currentIndex]);
+    }
+  }
+
+  const workerCount = Math.min(concurrency, items.length);
+  await Promise.all(Array.from({ length: workerCount }, () => runWorker()));
+}