fill gaps in env templates

desktop/connectionpetstore.properties.example

@@ -1,3 +1,7 @@
 url=jdbc:mysql://127.0.0.1:3306/Petstoredb?useSSL=false&allowPublicKeyRetrieval=true&serverTimezone=UTC
 user=petapp
-password=petapppass
+password=petapppass
+
+# Backend URL — swap comments to switch between local and remote
+api.baseUrl=http://localhost:8080
+#api.baseUrl=https://petshop-backend.nicepond-c7280126.westus2.azurecontainerapps.io