Build portfolio site - Astro + Tailwind, trilingual structure

- Astro 5.x + Tailwind CSS 4.x
- Dark theme with warm orange accent (#f97316)
- i18n routing: /en/, /de/, /es/ (English content complete, DE/ES placeholders)
- Components: Navbar, Hero, Services (4 cards), Projects (4 case studies), About, Contact, Footer
- Fade-in scroll animations
- Mobile-responsive with hamburger menu
- All content from content/*.md integrated
- SEO meta tags, Open Graph tags
- Clean build with no errors

public/favicon.svg

@@ -0,0 +1,4 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100">
+  <rect width="100" height="100" fill="#f97316"/>
+  <text x="50" y="70" font-size="60" text-anchor="middle" fill="white" font-family="sans-serif" font-weight="bold">P</text>
+</svg>