chore(strip): verwijder ongebruikte dependencies en marketing-restanten

- next-mdx-remote en gray-matter uit package.json (0 imports)
- components/ui/hero-section-2.tsx en timeline.tsx (nergens geimporteerd)
- lokale .DS_Store-bestanden opgeruimd (stonden al in .gitignore)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

package.json

@@ -53,10 +53,8 @@
     "cmdk": "^1.1.1",
     "date-fns": "^4.1.0",
     "framer-motion": "^12.23.24",
-    "gray-matter": "^4.0.3",
     "lucide-react": "^0.553.0",
     "next": "14.2.18",
-    "next-mdx-remote": "^5.0.0",
     "next-themes": "^0.4.6",
     "react": "18.3.1",
     "react-dom": "18.3.1",