fix(i18n): numbers, units, dates and order in the UI language, and after a switch (E30 S3)

Every locale formatter takes the language as an argument. Under the React
Compiler a formatter that read the i18n singleton was memoized on its other
arguments, so a card kept "2 hr 4 min" after a switch to Hungarian; plexLang()
had the same flaw and left Plex queries in the old language. Components now
take the language from useTranslation, and the signature makes forgetting it
a type error.

- ratings, file sizes, stream stats: the language's decimal mark ("8,3")
- view and subscriber counts compact in the language ("1,2 E")
- seconds as the language's unit ("6 mp") in the sliders and the stats
- a person's birth and death dates as dates, not ISO strings
- A-Z lists by the shown name in the language's alphabet (compareText),
  the tag catalog re-sorted by its translated names
- lint local/locale-format (was date-format) also refuses Intl.NumberFormat
  outside lib/format.ts, localeCompare, and a component reading the language
  off the i18n singleton

frontend/src/components/AccountPanel.tsx

@@ -55,7 +55,8 @@ export default function AccountPanel({
   user: AdminUserRow;
   onClose: () => void;
 }) {
-  const { t } = useTranslation();
+  const { t, i18n } = useTranslation();
+  const lang = i18n.language;
   const qc = useQueryClient();
   const [link, setLink] = useState<{ url: string; expires_at: string | null } | null>(null);
   const [copied, setCopied] = useState(false);
@@ -182,7 +183,7 @@ export default function AccountPanel({
               label={t("users.account.lastLogin")}
               value={
                 a.last_login_at
-                  ? formatDateTime(a.last_login_at)
+                  ? formatDateTime(a.last_login_at, lang)
                   : a.is_demo
                     ? t("users.account.lastLoginDemo")
                     : t("users.account.lastLoginNone")