feat(i18n): presentation extraction — t() call sites, data-i18n templates, locale selector

Route every application-owned presentation string through the i18n
core: t() call sites across the app/layers/ui/data/voice surfaces,
data-i18n* attributes in the src/ui/templates/*.html markup (applied at
boot by applyDocumentTranslations from src/standalone/application.js),
and the dock locale selector (runtime-rendered from the offered pair —
a single EN button while only English ships).

Rebased onto current main, where the extraction follows the module
splits: the shell wiring now lands in the owner modules
(panelChrome, visualSettings, locationNavigation, shareRestoration,
shellFeedback, applicationShell) and the voice status corpus in the
realtime* modules; scene status lives in director.js +
playbackAdapter.js.

Modules shared with the node runtime (loadingFeedback,
installationFeedback, regionalModel, keySetupCore, vessels ingestion)
stay environment-neutral English and localize at their browser render
sites (chip maps in shellFeedback/installations controls, the weather
table in cockpitBriefing, keySetupRequirementEnvVars compositions), so
the package-boundary graph stays clean; the browser boundary groups
now own the i18n modules they reach (scripts/package-boundaries.json).

src/keySetupCore.mjs

@@ -334,6 +334,19 @@ export function knownKeySetupEnvVars() {
 }
 
 /** Tooltip guidance for a control gated by one registry entry. */
+/**
+ * Env-var requirements for a registry entry, as machine values for
+ * presentation layers that localize the guidance sentence themselves
+ * (this module also runs in node-side key-setup builds, which stay English).
+ * @param {string} id Registry entry id.
+ * @returns {string|null} Joined env-var names, or null when nothing is required.
+ */
+export function keySetupRequirementEnvVars(id) {
+  const entry = KEY_SETUP_KEYS.find((candidate) => candidate.id === id);
+  if (!entry || entry.hidden) return null;
+  return entry.envVars.join(' + ');
+}
+
 export function keySetupRequirement(id) {
   const entry = KEY_SETUP_KEYS.find((candidate) => candidate.id === id);
   if (!entry || entry.hidden) return '';