♿️ Fix appearance switcher accessibility tooltips

Dynamically update the appearance switcher accessibility labels and tooltips using the native i18n variables so that the UI correctly reflects the user's localized language instead of hardcoded English strings.

layouts/partials/header/components/desktop-menu.html

@@ -24,9 +24,10 @@
     <div class="flex items-center">
       <button
         id="appearance-switcher"
-        aria-label="Dark mode switcher"
+        aria-label="{{ i18n "footer.dark_appearance" }}"
         type="button"
-        class="text-base bf-icon-color-hover">
+        class="text-base bf-icon-color-hover"
+        title="{{ i18n "footer.dark_appearance" }}">
         <div class="flex items-center justify-center dark:hidden">
           {{ partial "icon.html" "moon" }}
         </div>