Switch from histories -> derivations for showing derivation steps

[elmisback]

Herbie is removing histories from /alternatives response, we need to use the JSON derivations object to build the derivations properly!

[elmisback]

I drafted something for the JSON conversion which may or may not work as a drop-in in Claude https://claude.site/artifacts/aae60e4a-8a84-41a1-bdfa-5669df2e8ce9, the main issues are that we need to support LaTeX rendering for intermediate expressions and make sure the generation process matches/is close to what's in the original Racket code

[parthrdesai]

Will start working on this once fptaylor binaries are done

[elmisback]

I need to follow up on this

[elmisback]

https://claude.ai/share/fed22878-387a-46e6-ac51-a1f29a895b26