added read-only mode + visual improvements

pages/api/v1/users/index.ts

@@ -5,6 +5,12 @@ import verifyUser from "@/lib/api/verifyUser";
 
 export default async function users(req: NextApiRequest, res: NextApiResponse) {
   if (req.method === "POST") {
+    if (process.env.DEMO_MODE === "true")
+      return res.status(400).json({
+        response:
+          "This action is disabled because this is a read-only demo of Linkwarden.",
+      });
+
     const response = await postUser(req, res);
     return res.status(response.status).json({ response: response.response });
   } else if (req.method === "GET") {