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>

.gitignore

@@ -0,0 +1,6 @@
+node_modules/
+dist/
+.astro/
+.env
+.env.*
+!.env.example