The maniphest.points field is not exposed through the old maniphest.query method. Phragile need to switch to using the new maniphest.search method instead of maniphest.query.
I modified the maniphest cónduit controller and added the points field to the TaskInfoDictionaries.
I forked the maniphest.query and maniphest,info methods and added them as sprint.query and sprint.info.
This is assumed to be a temporary measure until upstream does this officially.
It's exposed through maniphest.search. This post has some discussion and links about the modern endpoints:
See https://secure.phabricator.com/D15244 for the upstream implementation.