Thank you for bringing this case to our attention. I understand that such kind of approach can be very useful for some situations, including consulting companies developers who are working with couple projects at the same time.
Right now there is no support for such functionality, but in the nearest future we will try to review the technical possibility to implement this and in case if it is possible we will add the ticket to our backlog. However, right now I won't be able to provide any, even approximate, timelines on when we can implement support for the per-project proxy configuration. In case if we would have some more users requesting the same feature we will do our best to reprioritize and complete it asap.