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/ui/RelativeTime.tsx

@@ -1,3 +1,4 @@
+import { useTranslation } from "react-i18next";
 import { formatDateTime, formatDateTimeSec, relativeFromMs } from "../../lib/format";
 
 // docs/DESIGN.md "Copy": a relative time ("3d ago") says how recent something is in a list, and the
@@ -16,14 +17,15 @@ export function RelativeTime({
   empty?: string;
   className?: string;
 }) {
+  const lang = useTranslation().i18n.language;
   const ms = typeof at === "number" ? at : at ? new Date(at).getTime() : NaN;
-  const text = Number.isFinite(ms) ? relativeFromMs(ms) : "";
+  const text = Number.isFinite(ms) ? relativeFromMs(ms, lang) : "";
   if (!text) return empty ? <span className={className}>{empty}</span> : null;
   const iso = new Date(ms).toISOString();
   return (
     <time
       dateTime={iso}
-      title={seconds ? formatDateTimeSec(iso) : formatDateTime(iso)}
+      title={seconds ? formatDateTimeSec(iso, lang) : formatDateTime(iso, lang)}
       className={className}
     >
       {text}