This doesn't sound like a case of you invading trust but her hypervigalence going into overdrive. She's trying to hold you responsible for the unresolved pain and trauma of past relationships, and it sounds like she isn't being fair to you. I can see why she would be jumpy, but at the same time, this is an extreme response. It's not like you were actively trying to search out private info. If you did it again and again and again, ok, I can see some room for her reaction. It sounds like she knew you were building the bookshelves... and probably knew you were clearing things off the shelves... right? Did you tell her you were doing this? If I hid something somewhere, like on a bookshelf, and I knew I hid stuff on it, and that my boyfriend was going to come in and build a new shelf, I would take off the really sensitive stuff I didn't want him to see before he was anywhere near it! Or I would ask him not too.
She might be unintentionally sabotaging things for herself out of anxiety of being too close than she can handle right now. I don't know.
Part of the balance supporters sometimes have to find, understanding the sufferer, accommodating them and their needs, but also not enabling sufferers being overly paranoid and jumpy. (There is potential for that to even make things worse over time - but that's a whole other subject.) You have needs too.
She may or may not be ready to be in a close relationship, and there may or may not be anything you can do about it - other than what you are already doing.
Is she in treatment?