Build multilingual POC Website Using Hugo and Book Theme

Create a small multilingual proof-of-concept (POC) website using the Hugo static site generator and the Hugo Book theme.

Requirements:
- Experience with Hugo and working with custom themes
- Ability to configure multilingual support
- Deliver a clean and working local development setup

Directory Structure:
The content should be placed in the following structure:

content/en/
- _index.md
- welcome.md
- product.md
- questions.md

content/de/
- _index.md
- willkommen.md
- produkt.md
- fragen.md

Expected URL Structure:

English content:
localhost:1313/en/ → content/en/_index.md
localhost:1313/en/welcome/ → welcome.md
localhost:1313/en/product/ → product.md
localhost:1313/en/questions/ → questions.md

German content (default language):
localhost:1313/ → content/de/_index.md
localhost:1313/willkommen/ → willkommen.md
localhost:1313/produkt/ → produkt.md
localhost:1313/fragen/ → fragen.md

Notes:
- The default language should be German and served without a language prefix
- The English version should be accessible via the /en/ prefix