>however, I started wondering if I shouldn't push her towards front-end

Yeah I would do the same

>i.e. HTML/CSS and eventually JS and a respectable framework or two. I did some substantial AngularJS projects a while back, so I could support her if we chose this direction. She is quite inclined towards design and has a good sense of color palettes, fonts, arrangements, etc. (IMHO).

Go for Vue, it's way easier to learn and to build small things quickly, and the doc is really well made so it will not be as frustrating as it could with angular