Initial commit: Luftglanz drone website with integrated AI chat assistant

Features:
- Complete Luftglanz drone cleaning website
- AI chat assistant integrated with OpenAI API
- Expert product advice for AGO Quart and Mellerud cleaning products
- Formal German language support (Sie form)
- Secure PHP backend for API calls
- Responsive design with mobile support
- Product-specific knowledge base
- Safety statements from manufacturers
- Multi-page integration (index, products, services, contact)

Technical components:
- AI chat widget (js/ai-chat.js)
- Chat styling (css/components/ai-chat.css)
- Backend API (ai-chat-api.php)
- Product knowledge base with detailed specifications
- Demo and documentation files

partials/nav.html

@@ -0,0 +1,24 @@
+<header>
+    <div class="container">
+        <div class="header-content">
+            <div class="logo">
+                <a href="../index.html" style="text-decoration: none; display: flex; align-items: center;">
+                    <img src="../images/favicon_logo.png" alt="Luftglanz Logo" class="logo-img">
+                    <h1 data-i18n="roof_drone">Luftglanz</h1>
+                </a>
+            </div>
+            
+            <nav class="main-nav" id="mainNav">
+                <ul>
+                    <li><a href="../index.html" data-i18n="nav_home">Home</a></li>
+                    <li><a href="../index.html#services" data-i18n="nav_services">Services</a></li>
+                    <li><a href="../index.html#how-it-works" data-i18n="nav_how_it_works">How It Works</a></li>
+                    <li><a href="../index.html#faq" data-i18n="nav_faq">FAQ</a></li>
+                    <li><a href="../index.html#contact" data-i18n="nav_contact">Contact</a></li>
+                    <li><a href="products.html" data-i18n="nav_products">Products</a></li>
+                    <li><a href="gallery.html" data-i18n="nav_gallery">Gallery</a></li>
+                </ul>
+            </nav>
+        </div>
+    </div>
+</header>