This is why Ardevia is not in the store anymore. Microsoft is changing their security rules from time to time. So our way to inject JS-Code to the site was approved with Ardevia in an earlier version, but since early 2016 Microsoft rejected the same technique, when we tried to submit the latest version. Therefore we needed to find another way to do it and the Foundation Add-In was the recommended way of Microsoft.
If requested we could also provide a full-trust Add-In to install manually. With this you don't need to install the Foundation Add-In anymore, but the update process will be manual in the future as well.