perf(media): optimize YouTube metadata loading

src/utils/mediaMetadata.ts

@@ -0,0 +1,27 @@
+import { invokeCommand as invoke } from '../ipc';
+import type { MediaMetadata } from '../bindings/MediaMetadata';
+
+type FetchMediaMetadataArgs = {
+  url: string;
+  cookieBrowser: string | null;
+  username: string | null;
+  password: string | null;
+};
+
+const inFlightMediaMetadata = new Map<string, Promise<MediaMetadata>>();
+
+const metadataKey = (args: FetchMediaMetadataArgs) =>
+  JSON.stringify([args.url, args.cookieBrowser, args.username, args.password]);
+
+export const fetchMediaMetadataDeduped = (args: FetchMediaMetadataArgs): Promise<MediaMetadata> => {
+  const key = metadataKey(args);
+  const existing = inFlightMediaMetadata.get(key);
+  if (existing) return existing;
+
+  const request = invoke('fetch_media_metadata', args)
+    .finally(() => {
+      inFlightMediaMetadata.delete(key);
+    });
+  inFlightMediaMetadata.set(key, request);
+  return request;
+};