fix(navigation): implement persistent shell with client-side highlighting for rock-solid mobile menu

partials/navigation.hbs

@@ -1,6 +1,10 @@
 <ul class="nav">
     {{#foreach navigation}}
-    <li class="{{link_class for=url class=(concat "nav-" slug)}}">
+    {{!-- 
+        We use Alpine to dynamically apply the nav-current class based on currentPath.
+        This works even when the navigation itself is not swapped by HTMX.
+    --}}
+    <li class="nav-{{slug}}" :class="currentPath === '{{url}}' ? 'nav-current' : ''">
         <a href="{{url absolute="true"}}" class="nav-link">
             {{label}}
         </a>