fix: add response.ok check in downloadMedia HTTP branch

Prevents saving error pages as media files when server returns non-2xx.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/utils/downloadMedia.ts

@@ -70,6 +70,10 @@ export async function downloadMedia(
   if (isHttp) {
     try {
       const response = await fetch(src);
+      if (!response.ok) {
+        console.error(`Failed to download: ${response.status} ${response.statusText}`);
+        return;
+      }
       const blob = await response.blob();
       const blobUrl = URL.createObjectURL(blob);
       triggerDownload(blobUrl, finalName);