feat: door access codes display and admin crud

templates/dashboard/index.html.twig

@@ -49,6 +49,15 @@
             <p class="text-sm text-gray-500 pb-4">Alle Buchungen verwalten.</p>
         </a>
 
+        <a href="{{ path('app_access_code') }}"
+           class="group flex flex-col rounded-md border border-gray-200 p-6 hover:border-primary hover:bg-gray-50">
+            <div class="flex items-center gap-3 pb-2">
+                {{ ux_icon('lucide:key-round', { class: 'h-6 w-6 shrink-0 text-primary' }) }}
+                <span class="text-lg font-bold">Zugangscodes</span>
+            </div>
+            <p class="text-sm text-gray-500 pb-4">Codes für Türen, Aufzug und Schranke.</p>
+        </a>
+
         {#
             The header is deliberately not navigation, so the dashboard is the only place an
             admin screen can be reached from.