However, none of these support rendering Latex or Mathjax
My current approach of generating PNG images from Latex and then rendering the PNGs as a graph using d3.js seems to work sufficiently well. I could modify the interface such that the existing webform is on the same page as the rendered graph.
The user would select an inference rule, provide the expressions, and render the graph all in a single page. What isn't clear in my mental model is how to connect edges to new steps.