improving ntfy error handling

lib/notification/adapter/ntfy.js

@@ -36,7 +36,17 @@ Link: ${newListing.link}`;
       method: 'POST',
       headers,
       body: message,
-    });
+    })
+      .then((res) => {
+        if (!res.ok) {
+          throw new Error(`Ntfy message could not be sent. Status code: ${res.status}`);
+        }
+        return res.text();
+      })
+      .catch((error) => {
+        // Ensure we reject with an Error object and prevent unhandled rejections
+        throw error instanceof Error ? error : new Error(String(error));
+      });
   });
 
   return Promise.all(promises);