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/voice/control.js

@@ -1,5 +1,5 @@
 import { nextTick } from 'vue';
-import { t } from '../i18n/index.js';
+import { onLocaleChange, t } from '../i18n/index.js';
 import { useVoiceStore } from '../ui/stores/voice.js';
 import { applicationPinia } from '../ui/vueRuntime.js';
 
@@ -73,30 +73,32 @@ function initialState(panel) {
       hidden: true,
       options: [],
       value: '',
-      title: t('Changing provider reconnects voice if it is on.'),
+      title: () => t('Changing provider reconnects voice if it is on.'),
     },
     tier: {
       hidden: false,
-      text: t('STD'),
+      text: () => t('STD'),
       pressed: false,
-      title: t('Voice model tier — applies next session'),
+      title: () => t('Voice model tier — applies next session'),
     },
     cost: {
       hidden: false,
       text: '~$0.00',
       level: 'ok',
-      title: t('Estimated session cost'),
+      title: () => t('Estimated session cost'),
     },
     costWarning: { hidden: true, text: '', level: null, title: null },
     button: {
-      label: t('Voice control — activate to toggle voice; hold Space to speak'),
+      label: () =>
+        t('Voice control — activate to toggle voice; hold Space to speak'),
       pressed: null,
     },
-    mic: { text: t('ON/OFF') },
-    status: { text: voiceStatusLabel('idle') },
-    detail: { text: t('VOICE STANDBY'), title: null },
+    mic: { text: () => t('ON/OFF') },
+    status: { text: () => voiceStatusLabel('idle') },
+    detail: { text: () => t('VOICE STANDBY'), title: null },
     help: {
-      text: t('Hold Space to speak · tap Space to activate focused controls'),
+      text: () =>
+        t('Hold Space to speak · tap Space to activate focused controls'),
     },
     error: { text: '' },
     voicePanel: {
@@ -107,14 +109,17 @@ function initialState(panel) {
       settingsExpanded: false,
       selected: 'preview',
     },
-    previewEmpty: { hidden: false, text: t('Voice replies appear here.') },
+    previewEmpty: {
+      hidden: false,
+      text: () => t('Voice replies appear here.'),
+    },
     preferences: {
       previewChecked: true,
       previewNote: '',
       timeoutChoice: '5',
       timeoutMinutes: '5',
       timeoutInputHidden: false,
-      timeoutNote: t('These preferences stay in this browser.'),
+      timeoutNote: () => t('These preferences stay in this browser.'),
       timeoutStatus: '',
       // Bumped by every owner write of the fields, so the view restores a
       // refused edit but leaves a draft alone across other renders.
@@ -164,7 +169,30 @@ export function createVoiceControl({
 } = {}) {
   const id = ++controlCount;
   const listeners = new Map();
+  // The fields given as functions, by part: they are called again when the
+  // locale changes, so the control's words follow the language.
+  const wording = new Map();
+  const word = (part, patch) => {
+    let fields = wording.get(part);
+    let worded = patch;
+    for (const [field, value] of Object.entries(patch)) {
+      if (typeof value !== 'function') {
+        fields?.delete(field);
+        continue;
+      }
+      if (!fields) wording.set(part, (fields = new Map()));
+      fields.set(field, value);
+      if (worded === patch) worded = { ...patch };
+      worded[field] = value();
+    }
+    return worded;
+  };
   let state = initialState(Boolean(panel));
+  for (const [part, value] of Object.entries(state))
+    if (part !== 'card' && value && typeof value === 'object')
+      state[part] = word(part, value);
+  // The default card's labels follow the locale until a card replaces it.
+  let defaultCard = true;
   // Each bar's `--audio-level` and `--audio-opacity`, or null at rest.
   let bars = null;
   let removed = false;
@@ -191,15 +219,21 @@ export function createVoiceControl({
     get state() {
       return state;
     },
-    /** Merge `patch` into one part of the control. */
+    /**
+     * Merge `patch` into one part of the control. A field given as a
+     * function is shown as what it returns, and called again when the
+     * locale changes; give translated words that way.
+     */
     update(part, patch) {
       if (removed) return;
-      state = { ...state, [part]: { ...state[part], ...patch } };
+      state = { ...state, [part]: { ...state[part], ...word(part, patch) } };
       publish();
     },
     /** Replace one part of the control. */
     replace(part, value) {
       if (removed) return;
+      wording.delete(part);
+      if (part === 'card') defaultCard = false;
       state = { ...state, [part]: value };
       publish();
     },
@@ -207,7 +241,8 @@ export function createVoiceControl({
      * Listen for an interaction the view reports: `button`, `tier`,
      * `provider-change`, `settings-button`, `settings-close`, `tab`,
      * `tab-keydown`, `panel-keydown`, `pointerenter`, `pointerleave`,
-     * `preview-change`, `timeout-select`, `timeout-input`, `card-dismiss`.
+     * `preview-change`, `timeout-select`, `timeout-input`, `card-dismiss`;
+     * and `locale` after a locale change, for an owner's own words.
      * @returns {() => void} Removes the listener.
      */
     on(name, listener) {
@@ -268,9 +303,21 @@ export function createVoiceControl({
         store.publishBars(null);
       }
       removed = true;
+      offLocale();
       listeners.clear();
     },
   };
+  const offLocale = onLocaleChange(() => {
+    if (removed) return;
+    for (const [part, fields] of wording) {
+      const patch = {};
+      for (const [field, value] of fields) patch[field] = value();
+      state = { ...state, [part]: { ...state[part], ...patch } };
+    }
+    if (defaultCard) state = { ...state, card: initialCard() };
+    publish();
+    ui.emit('locale');
+  });
   store.connect(ui);
   store.publishBars(null);
   publish();