Replace language switcher with Bootstrap dropdown

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

user/themes/natascha/templates/partials/langswitcher.html.twig

@@ -0,0 +1,20 @@
+{% extends 'partials/langswitcher-logic.html.twig' %}
+
+{% block language_block_start %}
+<li class="nav-item dropdown">
+    <a class="nav-link dropdown-toggle p-1" href="#" role="button" data-bs-toggle="dropdown" aria-expanded="false">
+        {{ langswitcher.current|upper }}
+    </a>
+    <ul class="dropdown-menu dropdown-menu-end">
+{% endblock %}
+
+{% block language_block_end %}
+    </ul>
+</li>
+{% endblock %}
+
+{% block language_item %}
+    {% if show_language and language != langswitcher.current %}
+    <li><a class="dropdown-item" href="{{ lang_url ~ uri.params ~ (uri.query|length > 1 ? '?' ~ uri.query) }}">{{ language|upper }}</a></li>
+    {% endif %}
+{% endblock %}