i18n: language picker in the bottom-right corner

Replaces the EN/ES/RU buttons in the Visual Presets dock with a picker
that scales to many languages: a globe button with the current code
next to the POWER UP chip, opening a list of languages named in their
own language with their codes, the current one first and checked. A
search field appears past 8 languages. Keyboard: arrows, Home/End,
Enter/Space, Esc, type-ahead; keys stay in the list while it is open.
Choosing a language still asks before dropping unsaved work, then
reloads. Phones get the globe alone and a full-width sheet; the layout
uses logical properties for right-to-left languages.

Co-Authored-By: Claude Opus 5.5 <[email protected]>

src/ui/templates/command-dock.html

@@ -10,8 +10,6 @@
         <span class="panel-title" data-i18n-runtime><span class="dock-label-icon dock-label-icon-presets" aria-hidden="true"></span>VISUAL PRESETS</span>
         <span class="panel-divider"></span>
       </button>
-      <!-- Language selector: buttons are rendered by applicationShell _initLocaleSelector(), one per shipped locale. -->
-      <div class="dock-locale-switch" role="group" data-i18n-aria-label aria-label="Language"></div>
       <div id="control-panel-popover" class="dock-popover-content">
       <button class="dock-pin-btn" data-pin-target="control-panel" type="button" aria-label="Pin visual presets" aria-pressed="false" title="Keep visual presets open" data-i18n-aria-label data-i18n-title><img src="/pin.svg" alt="" /></button>
       <div id="style-buttons" class="button-grid">

src/ui/templates/provider-settings.html

@@ -2,10 +2,16 @@
        both the chip and this dialog outright when /api/setup/status is not
        there to answer (prod builds, LAN visitors). Rows are rendered from
        that payload, so the key registry lives in src/keySetupCore.mjs alone. -->
-  <button id="key-setup-chip" type="button" hidden aria-haspopup="dialog" aria-controls="key-setup">
-    <span class="material-symbols-outlined" aria-hidden="true">bolt</span>
-    <span data-key-setup-chip-label data-i18n>POWER UP</span>
-  </button>
+  <!-- Bottom-right corner, one HUD row: the POWER UP chip (while keys are
+       missing) and, in the very corner, the interface language picker that
+       src/ui/localePicker.js renders into #locale-picker. -->
+  <div id="corner-actions">
+    <button id="key-setup-chip" type="button" hidden aria-haspopup="dialog" aria-controls="key-setup">
+      <span class="material-symbols-outlined" aria-hidden="true">bolt</span>
+      <span data-key-setup-chip-label data-i18n>POWER UP</span>
+    </button>
+    <div id="locale-picker"></div>
+  </div>
   <aside id="key-setup" role="dialog" aria-labelledby="key-setup-title" aria-describedby="key-setup-description" hidden>
     <div class="key-setup-scanline" aria-hidden="true"></div>
     <header class="key-setup-header">