Well, that sucks.

Here's the whole SCR 20:1.16, for reference.

I'm no lawyer, but I do believe she's not allowed to terminate representation without court approval, hence why she's asking you to sign a stipulation. (If you and her have agreed to the termination, the court would almost certainly approve it.)

I feel like there's some "my lawyer is a moron" motion you should be able to file, but I'm not sure exactly what it's called or what it asks for. (Maybe it only applies in criminal cases.)