fix: dates follow the UI language, not the browser's

Seven sites formatted with a bare toLocaleString()/toLocaleDateString(), so an
English UI on a Hungarian machine printed Hungarian-shaped dates (and the reverse).
They now go through formatDateTime/formatDate, which take the i18n language.

frontend/src/components/ShareDialog.tsx

@@ -9,6 +9,7 @@ import { useConfirm } from "./ConfirmProvider";
 import { notify } from "../lib/notifications";
 import { notifyActionError } from "../lib/actionErrors";
 import { copyText } from "../lib/clipboard";
+import { formatDate } from "../lib/format";
 import { api, type DownloadJob, type ShareLink } from "../lib/api";
 import { inputCls } from "./ui/form";
 import { Button } from "./ui/Button";
@@ -88,7 +89,7 @@ function UserShare({ job }: { job: DownloadJob }) {
 // --- share by public link -------------------------------------------------------------------
 
 function LinkRow({ link, onChanged }: { link: ShareLink; onChanged: () => void }) {
-  const { t } = useTranslation();
+  const { t, i18n } = useTranslation();
   const confirm = useConfirm();
   const [copied, setCopied] = useState(false);
   const [editPass, setEditPass] = useState(false);
@@ -130,7 +131,7 @@ function LinkRow({ link, onChanged }: { link: ShareLink; onChanged: () => void }
   if (link.allow_download) badges.push(t("downloads.share.downloadable"));
   if (link.expires_at)
     badges.push(
-      t("downloads.share.expiresOn", { date: new Date(link.expires_at).toLocaleDateString() }),
+      t("downloads.share.expiresOn", { date: formatDate(link.expires_at, i18n.language) }),
     );
 
   return (