feat(auth): enterprise authentication and user management

frontend/athena/components/LogoutButton.tsx

@@ -0,0 +1,33 @@
+"use client";
+
+import { useRouter } from "next/navigation";
+import { LogOut } from "lucide-react";
+
+import { Button } from "@/components/ui/button";
+
+export default function LogoutButton() {
+  const router = useRouter();
+
+  async function handleLogout() {
+    await fetch("/api/logout", {
+      method: "POST",
+    });
+
+    router.push("/login");
+    router.refresh();
+  }
+
+  return (
+    <Button
+      type="button"
+      variant="outline"
+      size="sm"
+      onClick={handleLogout}
+      aria-label="Abmelden"
+      title="Abmelden"
+    >
+      <LogOut size={16} />
+      Abmelden
+    </Button>
+  );
+}