fix: add missing i18n scripts to about.html

Critical Bug Fix:
- about.html had 55 data-i18n attributes but NO i18n scripts loaded
- Language selector appeared but clicking did nothing (confusing UX)

Added Before </body>:
- <script src="/js/i18n-simple.js"></script>
- <script src="/js/components/language-selector.js"></script>

Impact:
✅ about.html now fully functional in 3 languages (en/de/fr)
✅ All 55 translation keys now active
✅ Language switching works correctly

Testing:
- Verified scripts load after footer content
- Confirmed translation files accessible via HTTP
- Language selector now triggers content updates

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

public/about.html

@@ -280,5 +280,9 @@
     </div>
   </footer>
 
+  <!-- Internationalization -->
+  <script src="/js/i18n-simple.js"></script>
+  <script src="/js/components/language-selector.js"></script>
+
 </body>
 </html>