fix(archives): correct #1812 — Step 4 wiki link host

      Banner pointed to bambuddy.cool/wiki/getting-started/... which 404s;
      the wiki lives under the wiki.bambuddy.cool subdomain. Anchor was
      correct (MkDocs slug matches the existing "Step 4: Enable Store sent
      files on external storage" heading).

frontend/src/pages/ArchivesPage.tsx

@@ -3268,7 +3268,7 @@ export function ArchivesPage() {
             <div className="text-xs text-amber-200/80 mt-1">
               {t('archives.no3mfBanner.body')}{' '}
               <a
-                href="https://bambuddy.cool/wiki/getting-started/#step-4-enable-store-sent-files-on-external-storage"
+                href="https://wiki.bambuddy.cool/getting-started/#step-4-enable-store-sent-files-on-external-storage"
                 target="_blank"
                 rel="noreferrer"
                 className="underline hover:text-amber-100 inline-flex items-center gap-1"