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/cockpitController.js

@@ -32,7 +32,9 @@ import { createBriefState } from './cockpitBriefPages.js';
 import {
   createInstrumentState,
   createRouteState,
+  createVisionState,
 } from './cockpitInstrumentState.js';
+import { onLocaleChange } from '../i18n/index.js';
 import {
   publishBriefView,
   showBriefPage,
@@ -43,6 +45,7 @@ import {
   maybeRefreshRegionalBrief,
   renderRegionalBriefStatus,
   renderRegionalBrief,
+  relocalizeBrief,
 } from './cockpitBriefing.js';
 import {
   handleSignalClick,
@@ -189,7 +192,7 @@ export class CockpitViewController {
     this.scratchAnchorCartographic = new Cesium.Cartographic();
     this.scratchCameraCartographic = new Cesium.Cartographic();
     this.scratchTargetCartographic = new Cesium.Cartographic();
-    this._listenerRemovers = [];
+    this._listenerRemovers = [onLocaleChange(() => this.relocalize())];
 
     // Camera mutations belong before scene update/culling. Changing the camera
     // from preRender makes 3D Tiles discover a new view after traversal and can
@@ -356,6 +359,9 @@ export class CockpitViewController {
   renderRegionalBriefStatus(status, info) {
     return renderRegionalBriefStatus.call(this, status, info);
   }
+  relocalizeBrief() {
+    return relocalizeBrief.call(this);
+  }
   renderRegionalBrief(payload, info) {
     return renderRegionalBrief.call(this, payload, info);
   }
@@ -391,6 +397,36 @@ export class CockpitViewController {
     return handleSignalClick.call(this, event);
   }
 
+  /**
+   * Word every Cockpit surface again in the current locale. In flight the
+   * last reading is shown again; otherwise the surfaces go back to their
+   * placeholders, which the next entry replaces.
+   */
+  relocalize() {
+    if (this.destroyed) return;
+    this.relocalizeBrief();
+    this.publishVision(createVisionState(this.visionMode));
+    this.routeSignature = null;
+    if (this.active && this.lastAircraftInfo) {
+      this.rewordingSignals = true;
+      try {
+        this.updateHud(this.lastAircraftInfo, performance.now(), true);
+      } finally {
+        this.rewordingSignals = false;
+      }
+      return;
+    }
+    this.instruments = createInstrumentState();
+    this.publishInstrumentsView();
+    this.routeView = createRouteState();
+    this.publishRouteView();
+    this.contextView = {
+      ...createContextState(),
+      weather: this.contextView.weather,
+    };
+    this.publishContextView();
+  }
+
   /** Revoke new work before the shell awaits layer restoration. */
   stop() {
     if (this.destroyed) return;