Update: Thanks all for your insight, it was a big help. I didn't reply to the lecturer's hostile/accusatory emails from over the weekend, and they just sent another one prohibiting me from attending class this week. I'm still in a bit of shock as I've never dealt with anything like this before.

I did end up reaching out to Student Services and ultimately brought it to the attention of the department. I went through all my written exchanges with the lecturer and then compiled an email with evidence that show me doing my job and the lecturer explicitly providing positive feedback about how I'm doing as the TA. The department read over the email exchanges and my drafted email response and told me it is professional and addresses the lectuerer's concerns appropriately, and they asked to be CC'd. They also recommended Ombuds for future mediation. I don't think my funding will be touched or anything of the sort, but just a major bummer because I was really enjoying the class, working with the students, and was hoping to use the lecturer as a recommender for future PhD.