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/PlexPlaylistView.menu.dom.test.tsx

@@ -9,13 +9,16 @@ import { describe, it, expect, vi, beforeAll, afterEach } from "vitest";
 import { render, cleanup, screen, fireEvent, waitFor, act } from "@testing-library/react";
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
 
-vi.mock("react-i18next", async (importOriginal) => ({
-  ...(await importOriginal<typeof import("react-i18next")>()),
-  useTranslation: () => ({
-    t: (key: string, o?: { title?: string }) => (o?.title ? `${key}:${o.title}` : key),
-    i18n: { language: "en" },
-  }),
-}));
+vi.mock("react-i18next", async (importOriginal) => {
+  const real = (await import("i18next")).default;
+  return {
+    ...(await importOriginal<typeof import("react-i18next")>()),
+    useTranslation: () => ({
+      t: (key: string, o?: { title?: string }) => (o?.title ? `${key}:${o.title}` : key),
+      i18n: real,
+    }),
+  };
+});
 const h = vi.hoisted(() => ({ notify: vi.fn(), confirm: vi.fn(async () => true) }));
 vi.mock("../lib/notifications", async (importOriginal) => ({
   ...(await importOriginal<typeof import("../lib/notifications")>()),