Switch language in place, without a reload

Choosing a language in the picker now applies it at once. The choice is
stored and ?lang is kept in step through replaceState, and the picker keeps
focus.

Code that writes translated text itself re-presents it on a switch:
onLocaleChange() lets an owner listen, removed at teardown, and status
writers hand over a function of the locale (voice cards, scene director,
SDR, draw hints, imagery split, map sources, Bhote Koshi media) so the
words are rebuilt rather than re-sent. The HUD, cockpit, radio, CCTV,
launch, awareness and credit texts follow the same hook, and
applyDocumentTranslations can be applied again without undoing text code
wrote since.

The unsaved-work registry and persistLocaleAndReload existed only to guard
the reload, so they go, with their catalog entries.

src/ui/cockpitBriefing.js

@@ -8,7 +8,11 @@ import {
   formatCockpitCoordinate,
   formatCockpitWindDirection,
 } from './cockpitPresentation.js';
-import { COCKPIT_BRIEF_PAGES, CYCLE_HELP_KEYS } from './cockpitBriefPages.js';
+import {
+  COCKPIT_BRIEF_PAGES,
+  CYCLE_HELP_KEYS,
+  createBriefState,
+} from './cockpitBriefPages.js';
 
 // regionalModel.weatherCodeLabel is shared with node code and returns
 // English; translate it here.
@@ -58,15 +62,41 @@ export function showBriefPage(index, { manual = false } = {}) {
   this.scheduleContextLayout();
 }
 
+// The state is the accessible name; the help is the tooltip.
+function cycleWords(enabled) {
+  return {
+    autoRotate: enabled,
+    autoLabel: enabled ? t('CYCLE ON') : t('CYCLE OFF'),
+    autoHelp: t(CYCLE_HELP_KEYS[enabled ? 'on' : 'off']),
+  };
+}
+
+/**
+ * Word the briefing again in the current locale: its page, cycle toggle and
+ * whatever the regional card shows.
+ */
+export function relocalizeBrief() {
+  if (this.destroyed) return;
+  if (this.brief.news.state === null) {
+    const { news, local } = createBriefState();
+    this.brief.news = news;
+    this.brief.local = { ...local, coordinates: this.brief.local.coordinates };
+  }
+  Object.assign(this.brief, cycleWords(this.briefAutoRotateEnabled));
+  this.showBriefPage(this.briefPageIndex);
+  if (this.regionalBrief)
+    this.renderRegionalBrief(this.regionalBrief, this.lastAircraftInfo);
+  else if (this.brief.news.state)
+    this.renderRegionalBriefStatus(
+      this.brief.news.state,
+      this.lastAircraftInfo,
+    );
+}
+
 export function setBriefAutoRotate(enabled) {
   if (this.destroyed) return;
   this.briefAutoRotateEnabled = Boolean(enabled);
-  // The state is the accessible name; the help is the tooltip.
-  Object.assign(this.brief, {
-    autoRotate: this.briefAutoRotateEnabled,
-    autoLabel: this.briefAutoRotateEnabled ? t('CYCLE ON') : t('CYCLE OFF'),
-    autoHelp: t(CYCLE_HELP_KEYS[this.briefAutoRotateEnabled ? 'on' : 'off']),
-  });
+  Object.assign(this.brief, cycleWords(this.briefAutoRotateEnabled));
   this.publishBriefView();
   if (this.briefAutoRotateEnabled) this.startBriefRotation({ reset: true });
   else this.stopBriefRotation();