feat: make orders list clearer and put navbar globally except for admin area

shop/components/HeaderWrapper.tsx

@@ -0,0 +1,35 @@
+"use client";
+
+import { usePathname } from "next/navigation";
+
+interface HeaderWrapperProps {
+  navbar: React.ReactNode;
+  children: React.ReactNode;
+}
+
+export function HeaderWrapper({ navbar, children }: HeaderWrapperProps) {
+  const pathname = usePathname();
+  const isAdmin = pathname?.startsWith("/admin");
+
+  if (isAdmin) {
+    return <>{children}</>;
+  }
+
+  return (
+    <div className="flex flex-col min-h-screen bg-slate-50 text-slate-900 dark:bg-[#020617] dark:text-white">
+      {/* Demo Banner */}
+      <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>
+
+      {navbar}
+      
+      <main className="flex-1">
+        {children}
+      </main>
+    </div>
+  );
+}