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/PlexSidebar.tsx

@@ -44,7 +44,7 @@ const DURATION_BUCKETS: { key: string; min: number | null; max: number | null }[
 ];
 
 export default function PlexSidebar({ layout, setLayout, collapsed, onToggleCollapse }: Props) {
-  const { t } = useTranslation();
+  const { t, i18n } = useTranslation();
   // Scope / watch-state / sort / expanded filters live in PlexProvider (shared with PlexBrowse and
   // the header search box); this rail is the primary editor of them. Opening a playlist is a
   // hand-off to PlexBrowse via the shared `playlistOpen` slot.
@@ -60,7 +60,7 @@ export default function PlexSidebar({ layout, setLayout, collapsed, onToggleColl
   // Titles are display-only (chip labels) — keep them OUT of the facet query key so renaming/relabelling
   // never refetches. collectionMode stays IN the key: any/all changes the result set.
   const { collectionTitles: _cts, ...facetKey } = filters;
-  const lang = plexLang(); // HU/EN genre vocabulary — refetch facets on a language switch
+  const lang = plexLang(i18n.language); // HU/EN genre vocabulary — refetch facets on a language switch
   const facetsQ = useQuery({
     queryKey: qk.plexFacets(scope, show, facetKey, lang),
     queryFn: () => api.plexFacets(scope, filters, show, lang),