Add DSGVO-compliant cookie consent banner and fix navbar consistency

- Implement custom cookie consent banner with opt-in gating pattern
- Add comprehensive privacy documentation (DSGVO/GDPR compliant)
- Integrate consent management into production (index.html)
- Add multilingual support for cookie settings (DE/EN)
- Fix navbar font-size inconsistency across legal pages
- Include mobile.css in datenschutz.html and impressum.html
- Add complete implementation documentation

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

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

datenschutz.html

@@ -6,6 +6,7 @@
     <title>Datenschutz - IntelSight</title>
     <link rel="stylesheet" href="css/main.css">
     <link rel="stylesheet" href="css/fonts.css">
+    <link rel="stylesheet" href="css/mobile.css">
     <style>
         body {
             background: #0a0f1c;