I'm the PP who posted earlier about it being about more than the issue at hand. After reading your later post, though, I actually think it might be more about executive function than you are realizing. Sure, the other stuff is probably there, too, but consider this as an option:
Maybe she has the idea and genuinely wants to move it forward (i.e. paint her room) but is unable to initiate the action. She might actually feel that she has launched this into action by telling you about it and does not have the capacity to move it beyond that herself. So, she is perceiving this as stalled because you aren't moving it forward, and when you remind her that you want to, she feels some level of shame and anger toward herself that she didn't actually move it forward (maybe she doesn't even realize this is happening in the moment, even if she feels like this).
I could be totally wrong, but I'm thinking of my own DC (AuDHD), who would mention something offhand in a totally random time and then be upset with me that I didn't follow up on it. Like: I'm dropping him off at school and in a hurry to get to work. As he jumps out of the car, he randomly says, "Hey, I want to get a new desk chair at home. Oh, also, here's a crumb I found on the floor. See you later!" He doesn't seem particularly worked up about it, and since he hops out of the car and I go to work right after, I don't remember it and he doesn't mention it again, even while using the desk chair. Then, two months later, he's like, "Why didn't you get me a new desk chair?" In his mind, he raised the flag about it, even though he didn't really seem very invested in it, but that's his communication style, and I sometimes forget it is different from others.
The main difference there is that he is too young to really be involved in it, and he generally won't get angry if I bring it up again. Maybe your DD is also a little uncomfortable about asking for things from you, like it will make her feel indebted to you or something, if she has some attachment issues?