Unify layouts and create CatalogPage component

- MainNavigation: center tabs on page (absolute positioning)
- SubNavigation: align left instead of center
- Create CatalogPage universal component for list+map pages
- Migrate catalog pages (offers, suppliers, hubs) to CatalogPage
- Remove PageHeader from clientarea pages (redundant with navigation)
- Add topnav layout to supplier detail page

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/components/navigation/MainNavigation.vue

@@ -1,6 +1,6 @@
 <template>
   <header class="sticky top-0 z-40 bg-base-100 border-b border-base-300">
-    <div class="flex items-center justify-between h-16 px-4 lg:px-6">
+    <div class="relative flex items-center h-16 px-4 lg:px-6">
       <!-- Left: Logo -->
       <div class="flex items-center">
         <NuxtLink :to="localePath('/')" class="flex items-center gap-2">
@@ -8,8 +8,8 @@
         </NuxtLink>
       </div>
 
-      <!-- Center: Main tabs -->
-      <nav class="hidden md:flex items-center gap-1">
+      <!-- Center: Main tabs (absolutely centered on page) -->
+      <nav class="hidden md:flex items-center gap-1 absolute left-1/2 -translate-x-1/2">
         <NuxtLink
           v-for="tab in visibleTabs"
           :key="tab.key"
@@ -22,7 +22,7 @@
       </nav>
 
       <!-- Right: Globe + Team + User -->
-      <div class="flex items-center gap-2">
+      <div class="flex items-center gap-2 ml-auto">
         <!-- Globe (language/currency) dropdown -->
         <div class="dropdown dropdown-end">
           <button tabindex="0" class="btn btn-ghost btn-circle">