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/pages/catalog/suppliers/[id].vue

@@ -107,6 +107,10 @@ import {
   GetOffersDocument,
 } from '~/composables/graphql/public/exchange-generated'
 
+definePageMeta({
+  layout: 'topnav'
+})
+
 const route = useRoute()
 const localePath = useLocalePath()
 const { t } = useI18n()