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/PlexPlayer.tsx

@@ -145,7 +145,7 @@ export default function PlexPlayer({ itemId, onClose, queue, fromStart = false }
   const qc = useQueryClient();
   const [id, setId] = useState(itemId);
   // Serve the player's title/summary/rich detail in the active language (E5 S6), matching the grid.
-  const lang = plexLang();
+  const lang = plexLang(i18n.language);
   const detailQ = useQuery({
     queryKey: qk.plexItem(id, lang),
     queryFn: () => api.plexItem(id, lang),
@@ -986,7 +986,7 @@ export default function PlexPlayer({ itemId, onClose, queue, fromStart = false }
         seekTo(playhead(absRef, loadStartRef) + zone * TAP_SKIP_S);
         flashOsd(
           t(zone < 0 ? "plex.player.tapBack" : "plex.player.tapForward", {
-            d: formatUnit(skips * TAP_SKIP_S, "second"),
+            d: formatUnit(skips * TAP_SKIP_S, "second", lang),
           }),
         );
         return;
@@ -999,7 +999,7 @@ export default function PlexPlayer({ itemId, onClose, queue, fromStart = false }
       }
       toggleControls();
     },
-    [togglePlay, showControls, toggleControls, seekTo, flashOsd, t, uiVisible],
+    [togglePlay, showControls, toggleControls, seekTo, flashOsd, t, lang, uiVisible],
   );
 
   // Auto-skip intro/credits (countdown → jump to marker end / next item). The refs bridge to the