fix(admin): persist data directory and pass env vars

app/api/admin/logout/route.ts

@@ -0,0 +1,8 @@
+import { NextResponse } from "next/server";
+import { adminSessionCookie } from "@/lib/admin/auth";
+
+export async function POST() {
+  const response = NextResponse.json({ message: "Abgemeldet." });
+  response.cookies.set(adminSessionCookie, "", { path: "/", maxAge: 0 });
+  return response;
+}