Make the primary nav customer-facing and keep the services submenu readable.

Stack and the CV leave the chrome so Contact stays the main action. The desktop submenu now uses an opaque surface token and a stacking context above page content.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/app/core/navigation/navigation.ts

@@ -38,10 +38,6 @@ export const PRIMARY_NAV: readonly NavItem[] = [
     routeId: 'projects',
     label: { de: 'Projekte', en: 'Projects' },
   },
-  {
-    routeId: 'stack',
-    label: { de: 'Stack', en: 'Stack' },
-  },
   {
     routeId: 'about',
     label: { de: 'Über mich', en: 'About' },