i18n: translate the application views with t() as they render

Every data-i18n, data-i18n-title, data-i18n-aria-label and
data-i18n-placeholder marker in the Vue templates becomes a t() call with
the key the boot pass used to look up, contexts included. The three labels
the shell rewrote at boot (Visual Presets, Location and the standby
description) render through t() too, and that rewrite is gone. With the
locale in vue-i18n, view text now follows a locale change, and markup
under v-if or v-for no longer comes back in English when it re-renders.

Rendered text and attributes are unchanged in every locale. The boot pass
still translates static page markup such as the loading screen and a host's
own markup, and npm run i18n rejects data-i18n* in a Vue template.

src/ui/views/SceneChromeView.vue

@@ -63,7 +63,7 @@ const vToastText = {
   <div id="world-overlay-root" aria-hidden="true">
     <canvas id="world-overlay-canvas"></canvas>
   </div>
-  <div id="world-overlay-actions" class="world-overlay-accessibility" role="region" aria-label="Visible map targets" data-i18n-aria-label>
+  <div id="world-overlay-actions" class="world-overlay-accessibility" role="region" :aria-label="t('Visible map targets')">
     <div id="world-overlay-action-list"><UiButton v-for="item in targets?.items ?? []" :key="item.key" :aria-label="item.label" :pressed="Boolean(item.selected)" :data-overlay-action-key="item.key" :onClick="onOverlayAction(targets.owner, item.key)">{{ item.label }}</UiButton></div>
     <div id="world-overlay-status" v-overlay-status="targets" role="status" aria-live="polite" aria-atomic="true"></div>
   </div>
@@ -72,13 +72,13 @@ const vToastText = {
   <div id="title-bar">
     <div class="title-glow"></div>
     <h1><span class="title-logo brand-logo" data-logo-gaze data-logo-src="/logo.svg" aria-hidden="true"><img src="/logo.svg" alt="" /></span> <span translate="no">GOD'S EYE <span class="title-accent">VIEW</span></span></h1>
-    <p class="subtitle scene-text-holdout" data-i18n>NO PLACE LEFT BEHIND</p>
+    <p class="subtitle scene-text-holdout">{{ t('NO PLACE LEFT BEHIND') }}</p>
     <div v-if="fps" class="frame-rate-readout scene-text-holdout" :hidden="!fps.visible" :title="t('Rendered globe frames per second · toggle with `')">{{ fps.text }}</div>
   </div>
 
   <!-- Style indicator -->
   <div id="style-indicator">
-    <span class="indicator-label scene-text-holdout" data-i18n>ACTIVE STYLE</span>
+    <span class="indicator-label scene-text-holdout">{{ t('ACTIVE STYLE') }}</span>
     <span class="indicator-value scene-text-holdout" id="active-style-name">{{ style ? style.label : t('NORMAL') }}</span>
   </div>