Add centralized saveMedia helpers for image, video, and file downloads.

Platforms can register a custom saver; viewers share one download/save path instead of FileSaver call sites.

src/app/components/Pdf-viewer/PdfViewer.tsx

@@ -5,7 +5,7 @@ import classNames from 'classnames';
 import { Box, Button, Chip, Header, IconButton, Input, Menu, PopOut, RectCords, Scroll, Spinner, Text, as, config } from 'folds';
 import { Icon, Icons } from '../icons';
 import FocusTrap from 'focus-trap-react';
-import FileSaver from 'file-saver';
+import { saveMediaBlob } from '../../utils/saveMedia';
 import * as css from './PdfViewer.css';
 import { AsyncStatus } from '../../hooks/useAsyncCallback';
 import { useZoom } from '../../hooks/useZoom';
@@ -61,8 +61,14 @@ export const PdfViewer = as<'div', PdfViewerProps>(
       }
     }, [docState, pageNo, zoom]);
 
-    const handleDownload = () => {
-      FileSaver.saveAs(src, name);
+    const handleDownload = async () => {
+      try {
+        const res = await fetch(src);
+        if (!res.ok) throw new Error('Failed to fetch PDF');
+        await saveMediaBlob(await res.blob(), name);
+      } catch (error) {
+        console.warn('[PdfViewer] Failed to download:', error);
+      }
     };
 
     const handleJumpSubmit: FormEventHandler<HTMLFormElement> = (evt) => {