Add the media downloader with hash storage and local file serving

media-scrape/src/types.ts

@@ -83,6 +83,10 @@ export interface ScrapeMeta {
     media: Record<MediaKind, number>;
     errors: number;
     lastError: string | null;
+    /** Files fetched in download mode. */
+    downloaded?: number;
+    /** Files that failed after retries; skipped URLs are not counted here. */
+    downloadErrors?: number;
 }
 
 export function emptyMediaCounts(): Record<MediaKind, number> {