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/lib/plexStats.ts

@@ -2,8 +2,13 @@
 // React/DOM so the number-crunching is unit-testable: the component gathers raw values off videoRef /
 // hlsRef and hands them here; this returns i18n-keyed rows the overlay renders. No data pipeline — the
 // HTML5 <video> + hls.js already expose everything (intrinsic dims, getVideoPlaybackQuality, levels).
+// The numbers are in the UI language (E30 S3: "4,2 Mbps", "12,3 mp" in Hungarian); the unit symbols of a
+// stream (Mbps, kbps) are the same in both.
+
+import { formatDecimal, formatNumber, formatUnit } from "./format";
 
 export interface PlexStatsInput {
+  lang: string; // the UI language, for the numbers
   // The item's codec classification (backend `classify_playable`): the "active mode" a viewer cares
   // about — direct copy, remux (stream-copy → HLS), or transcode (re-encode). Empty until detail loads.
   playable: string; // "direct" | "remux" | "transcode" | ""
@@ -53,23 +58,24 @@ export interface StatRow {
 const DASH = "—";
 
 // bits-per-second → "4.2 Mbps" / "820 kbps". Undefined/0 → dash (hls.js reports 0 before a level loads).
-export function fmtBitrate(bps: number | undefined): string {
+export function fmtBitrate(bps: number | undefined, lang: string): string {
   if (!bps || bps <= 0) return DASH;
-  if (bps >= 1_000_000) return `${(bps / 1_000_000).toFixed(1)} Mbps`;
-  return `${Math.round(bps / 1000)} kbps`;
+  if (bps >= 1_000_000) return `${formatDecimal(bps / 1_000_000, lang)} Mbps`;
+  return `${formatNumber(Math.round(bps / 1000), lang)} kbps`;
 }
 
-// Seconds of buffer ahead of the playhead → "12.3 s".
-export function fmtBufferSecs(s: number): string {
+// Seconds of buffer ahead of the playhead → "12.3 sec" / "12,3 mp".
+export function fmtBufferSecs(s: number, lang: string): string {
   if (!Number.isFinite(s) || s < 0) return DASH;
-  return `${s.toFixed(1)} s`;
+  return formatUnit(s, "second", lang, 1);
 }
 
 // Dropped / total decoded frames, with a drop percentage once any frames have been decoded.
-export function fmtFrames(dropped: number, total: number): string {
+export function fmtFrames(dropped: number, total: number, lang: string): string {
   if (total <= 0) return DASH;
   const pct = (dropped / total) * 100;
-  return `${dropped} / ${total} (${pct.toFixed(pct < 1 ? 2 : 1)}%)`;
+  const n = (x: number) => formatNumber(x, lang);
+  return `${n(dropped)} / ${n(total)} (${formatDecimal(pct, lang, pct < 1 ? 2 : 1)}%)`;
 }
 
 // Intrinsic decoded resolution. 0×0 means the browser hasn't decoded (or can't) — an honest dash,
@@ -146,7 +152,7 @@ export function buildStatRows(s: PlexStatsInput): StatRow[] {
       {
         key: "bitrate",
         labelKey: "plex.player.stats.bitrate",
-        value: fmtBitrate(s.measuredBps),
+        value: fmtBitrate(s.measuredBps, s.lang),
       },
       { key: "level", labelKey: "plex.player.stats.level", value: fmtLevel(s.hlsLevel) },
     );
@@ -159,9 +165,13 @@ export function buildStatRows(s: PlexStatsInput): StatRow[] {
     {
       key: "frames",
       labelKey: "plex.player.stats.frames",
-      value: fmtFrames(s.droppedFrames, s.totalFrames),
+      value: fmtFrames(s.droppedFrames, s.totalFrames, s.lang),
+    },
+    {
+      key: "buffer",
+      labelKey: "plex.player.stats.buffer",
+      value: fmtBufferSecs(s.bufferAheadS, s.lang),
     },
-    { key: "buffer", labelKey: "plex.player.stats.buffer", value: fmtBufferSecs(s.bufferAheadS) },
     { key: "offset", labelKey: "plex.player.stats.offset", value: fmtClock(s.sessionStartS) },
     {
       key: "position",