feat: add admin settings page with toggle switch for demo banner

shop/app/admin/einstellungen/page.tsx

@@ -0,0 +1,33 @@
+'use client';
+
+import { useState, useEffect } from 'react';
+import { Switch } from '@/components/ui/switch';
+
+export default function AdminSettings() {
+  const [demoActive, setDemoActive] = useState(true);
+
+  useEffect(() => {
+    const state = localStorage.getItem('demo_banner_disabled') !== 'true';
+    setDemoActive(state);
+  }, []);
+
+  const toggleDemo = (checked: boolean) => {
+    setDemoActive(checked);
+    localStorage.setItem('demo_banner_disabled', (!checked).toString());
+    // Event feuern, damit andere Tabs/Komponenten sofort updaten
+    window.dispatchEvent(new Event('storage_demo_changed'));
+  };
+
+  return (
+    <div className="p-6 max-w-xl mx-auto text-slate-900 dark:text-white">
+      <h1 className="text-2xl font-bold mb-6">Admin Einstellungen</h1>
+      <div className="flex items-center justify-between p-4 bg-slate-100 dark:bg-white/5 rounded-xl border border-slate-200 dark:border-white/10">
+        <div>
+          <p className="font-medium text-slate-900 dark:text-white">Demo-Warnmeldungen</p>
+          <p className="text-xs text-slate-500 dark:text-slate-400">Schaltet gelbe Banner ein oder aus.</p>
+        </div>
+        <Switch checked={demoActive} onCheckedChange={toggleDemo} />
+      </div>
+    </div>
+  );
+}

shop/app/page.tsx

@@ -7,7 +7,7 @@ export default function Home() {
   return (
     <div className="flex flex-col min-h-screen bg-slate-50 text-slate-900 dark:bg-[#020617] dark:text-white">
       {/* Demo Banner */}
-      <div className="bg-amber-500/10 border-b border-amber-500/20 py-2 px-4 text-center text-xs text-amber-600 dark:text-amber-400 font-medium tracking-wide z-50">
+      <div id="demo-banner" className="bg-amber-500/10 border-b border-amber-500/20 py-2 px-4 text-center text-xs text-amber-600 dark:text-amber-400 font-medium tracking-wide z-50">
         ⚠️ Dies ist eine **Demo-Webseite (Dummy-Shop)**. Es werden keine echten Bestellungen verarbeitet oder Zahlungen abgewickelt.
       </div>
 
@@ -24,7 +24,7 @@ export default function Home() {
                   CASPOS Lizenz-Management-Server
                 </div>
                 <h1 className="text-3xl font-bold tracking-tighter sm:text-4xl md:text-5xl lg:text-7xl/none">
-                  POS Software <span className="text-blue-600 dark:text-blue-500">Lizenzen & Add-ons</span>
+                  POS Software <span className="text-blue-600 dark:text-blue-500">Lizenzen & Module</span>
                 </h1>
                 <p className="mx-auto max-w-[700px] text-slate-600 dark:text-slate-400 md:text-xl mt-6">
                   Erwerben und verwalten Sie digitale Lizenzen für CASPOS Kassensysteme. Sofortige Aktivierung und automatische Bereitstellung für Ihre Kunden.

shop/components/ui/switch.tsx

@@ -0,0 +1,41 @@
+"use client";
+
+import * as React from "react";
+import { cn } from "@/lib/utils";
+
+interface SwitchProps extends React.InputHTMLAttributes<HTMLInputElement> {
+  checked?: boolean;
+  onCheckedChange?: (checked: boolean) => void;
+}
+
+const Switch = React.forwardRef<HTMLInputElement, SwitchProps>(
+  ({ className, checked, onCheckedChange, ...props }, ref) => {
+    const handleChange = (e: React.ChangeEvent<HTMLInputElement>) => {
+      onCheckedChange?.(e.target.checked);
+    };
+
+    return (
+      <label className="relative inline-flex items-center cursor-pointer select-none">
+        <input
+          type="checkbox"
+          className="sr-only peer"
+          checked={checked}
+          onChange={handleChange}
+          ref={ref}
+          {...props}
+        />
+        <div className={cn(
+          "w-11 h-6 bg-slate-200 rounded-full peer dark:bg-slate-700",
+          "peer-focus:outline-none peer-focus:ring-2 peer-focus:ring-blue-500/50",
+          "peer-checked:after:translate-x-full rtl:peer-checked:after:-translate-x-full peer-checked:after:border-white",
+          "after:content-[''] after:absolute after:top-[2px] after:start-[2px] after:bg-white after:border-slate-300 after:border after:rounded-full after:h-5 after:w-5 after:transition-all dark:border-slate-600",
+          "peer-checked:bg-blue-600"
+        )} />
+      </label>
+    );
+  }
+);
+
+Switch.displayName = "Switch";
+
+export { Switch };