feat: offcanvas mobile navigation with user avatar and admin bar fix (v1.0.11)

Switch mobile nav from collapse to offcanvas, add logged-in user avatar
and My Account link to offcanvas header, move dark mode toggle to
offcanvas footer. Fix admin bar overlapping offcanvas via inline CSS.

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

views/base.html.twig

@@ -11,7 +11,7 @@
     <a class="wp-bootstrap-skip-link" href="#main-content">{{ __('Skip to main content') }}</a>
 
     {% block header %}
-        {% include 'partials/header.html.twig' %}
+        {% include 'partials/header-offcanvas.html.twig' %}
     {% endblock %}
 
     <main id="main-content" class="{% block main_class %}py-4{% endblock %}">