You need to sit down and talk, that's what you need to do.
Explain that you now understand that you made a bad mistake, you were still thinking of her as a little girl, and you now understand that this has made her life more difficult than it need have been.
For your own reference, this is as if you had had a misunderstanding at work and your mum, or your husband phoned in to lay into them: it would take a while to live that down with your colleagues- and pointing this out to your parent/spouse would not be a case of "attitude".
(15yos have a lot of attitude, but they need to learn the difference between attitude and legitimate grievances, and that won't be helped if we as parents treat everything we don't like as "attitude")
tell her that you want to avoid making that mistake again
tell her that while all the usual rules of behaviour still apply, you understand that you need to start communicating more as adults
tell her that from now on, you will not take steps behind her back unless you actually believe her life is in danger or she is putting somebody else in danger (and make it very clear that you do not anticipate either of those contingencies)
tell her that you will discuss it with her before you do anything in the future and that it is time you started working together
tell her that you may ask her what she wants you to do and that you will expect her to answer in a rational way but that you will listen
tell her that from now on she can tell you things in confidence and unless specifically instructed, you will assume that she is just blowing off steam
and then point out that though you are aware you made a mistake, her part of the being-treated-as-an-adult deal is to still treat you as an adult would if somebody lets them down: not by name-calling or door-slamming or any of the things that she has never seen you do (I hope) when an adult has let you down