feat: add responsive mobile navigation, fix horizontal scroll overflow, and add toggleable real corporate login view with demo autofill

app/templates/base.html

@@ -14,9 +14,14 @@
       <a href="/" class="brand">
         🥨 <span>Schmankerl</span> <small class="tenant-badge">{{ tenant.name if tenant else 'Portal' }}</small>
       </a>
-      <nav class="nav-links">
+      <button class="mobile-toggle" aria-label="Menü öffnen" id="mobileNavToggle" aria-expanded="false">
+        <span class="bar"></span>
+        <span class="bar"></span>
+        <span class="bar"></span>
+      </button>
+      <nav class="nav-links" id="navLinks">
         {% if current_user %}
-        <a href="/">Brotzeit bestellen</a>
+        <a href="/">🥨 Brotzeit bestellen</a>
         {% if current_user.role == 'admin' %}
         <a href="/admin" class="nav-admin">👨‍🍳 Einkäufer-Cockpit</a>
         {% endif %}
@@ -43,5 +48,25 @@
     </div>
   </footer>
 
+  <script>
+    const navToggle = document.getElementById('mobileNavToggle');
+    const navLinks = document.getElementById('navLinks');
+    if (navToggle && navLinks) {
+      navToggle.addEventListener('click', () => {
+        const isOpen = navLinks.classList.toggle('open');
+        navToggle.classList.toggle('open', isOpen);
+        navToggle.setAttribute('aria-expanded', isOpen);
+        document.body.style.overflow = isOpen ? 'hidden' : '';
+      });
+      navLinks.querySelectorAll('a').forEach(link => {
+        link.addEventListener('click', () => {
+          navLinks.classList.remove('open');
+          navToggle.classList.remove('open');
+          navToggle.setAttribute('aria-expanded', 'false');
+          document.body.style.overflow = '';
+        });
+      });
+    }
+  </script>
 </body>
 </html>