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/Home.tsx

@@ -30,7 +30,13 @@ import {
 } from "../lib/api";
 import { notifyActionError } from "../lib/actionErrors";
 import { takeSurprise, useSurpriseRequest } from "../lib/homeIntent";
-import { formatDuration, formatRuntime, formatViews, relativeTime } from "../lib/format";
+import {
+  formatCompact,
+  formatDecimal,
+  formatDuration,
+  formatRuntime,
+  relativeTime,
+} from "../lib/format";
 import { toggleWatchState } from "../lib/plexWatch";
 import { useComfortPin, pinTargetForCard, shelfMoveTarget, type ShelfMove } from "./comfortPin";
 import { type ActionMenuItem } from "./ui/ActionMenu";
@@ -502,7 +508,8 @@ function Hero({
   onReroll: () => void;
   rerolling: boolean;
 }) {
-  const { t } = useTranslation();
+  const { t, i18n } = useTranslation();
+  const lang = i18n.language;
   // The hero is a card like any other (the owner, 2026-09-27): the same hover row on its picture and
   // the same whole action list on its "…", right-click and long-press — it was a pin row alone.
   const { menu, items, panels, plexAdd } = useHomeCardMenu({
@@ -533,12 +540,12 @@ function Hero({
   const plex = card.plex;
   const video = card.video;
   const facts = plex
-    ? [plex.year, formatRuntime(card.duration_seconds)]
+    ? [plex.year, formatRuntime(card.duration_seconds, lang)]
     : video
       ? // The channel is the subtitle already.
         [
-          video.view_count != null && `${formatViews(video.view_count)} ${t("card.views")}`,
-          relativeTime(video.published_at),
+          video.view_count != null && `${formatCompact(video.view_count, lang)} ${t("card.views")}`,
+          relativeTime(video.published_at, lang),
         ]
       : [];
   const factLine = facts.filter(Boolean).join(" · ");
@@ -631,7 +638,7 @@ function Hero({
               <span className="inline-flex items-center gap-0.5">
                 {factLine && <span aria-hidden>·</span>}
                 <Star className="h-3 w-3 fill-current text-rating" aria-hidden />
-                {plex.rating.toFixed(1)}
+                {formatDecimal(plex.rating, lang)}
               </span>
             )}
           </p>
@@ -692,7 +699,7 @@ function readSavedQuestion(): SavedQuestion | null {
 }
 
 export default function Home() {
-  const { t } = useTranslation();
+  const { t, i18n } = useTranslation();
   const qc = useQueryClient();
   const { setPage } = useNavigationActions();
   const { setJumpTo } = usePlexActions();
@@ -722,7 +729,7 @@ export default function Home() {
   const [player, setPlayer] = useState<{ video: Video; startAt: number | null } | null>(null);
 
   // A Plex card's title is in the reader's language (E30), so the answer is cached per language.
-  const lang = plexLang();
+  const lang = plexLang(i18n.language);
   const q = useQuery({
     queryKey: qk.discover(budget, lang),
     queryFn: () => api.discover(budget, 0, lang),