My main question is around the use of color. I'd argue the error states - conflicts, diverging branches, etc - should be the ones in red, since those are the issues you want to call the most attention to.
Getting rid of any chartjunk is the other big thing. Using four characters of every prompt just for `git:` is not reasonable. And as much as I like the idea of being warned about untracked files, I fear that in most real situations you end up with random scratch files in the same directory. My prompt would always say `7A` at the end, wasting more space (and mental effort!).
Good work!