Initial Astro + Tailwind scaffold for Wohlruf landing page

- Astro static site generator with zero-JS default output
- Tailwind CSS for styling (consistent with main app stack)
- German-language landing page: hero, how-it-works, features, pricing, FAQ, CTA
- Placeholder pages for Impressum, Datenschutz, AGB
- Reusable Header/Footer/Base layout components
- FTP-deployable static output via `npm run build`
- README with content TODO list for CMO

Co-Authored-By: Paperclip <noreply@paperclip.ing>

tsconfig.json

@@ -0,0 +1,5 @@
+{
+  "extends": "astro/tsconfigs/strict",
+  "include": [".astro/types.d.ts", "**/*"],
+  "exclude": ["dist"]
+}