The part that bothered me most about the situation (and I realize that it's only your side being told here) is that she gave lots of warning signs that she was

The part that bothered me most about the situation (and I realize that it's only your side being told here) is that she gave lots of warning signs that she was not holding up her side of any form of partnership. If she couldn't show up to the meetings, give you feedback on the tasks that you were tracking, prepare for your discussions of the app, etc... you should have run away from her right there. Never stay involved with partners who aren't adding their share of value in an undertaking. Since she wasn't paying you or even offering equity, the least she could have done is to participate in the work that you were doing for her benefit. Don't tolerate being systematically disrespected.