EPUB: Render TeX with MathJax

[AbeJellinek]

Example EPUB: https://www.core-econ.org/wp-content/uploads/2024/10/the-economy-2-0-microeconomics-epub.epub

MathJax is a big library (it doubles the size of reader.js when imported statically), so we import it dynamically when a book actually needs it. Other than that, everything we're doing here is pretty straightforward. There's a new context menu item (Copy TeX) that will need its string copied over to the client.

https://forums.zotero.org/discussion/121716/epub-tex-not-typeset

[mrtcode]

It works as expected. It’s a bit painful to add an extra 2.5 MB (less than 700 KB after compressing) to Zotero just to render formulas in some EPUBs, but that’s the cost of supporting EPUBs.

Anyway, looks good.

[AbeJellinek]

Yeah, it is a little painful. It would be better if we could use KaTeX - since the note editor already uses that, it would gzip down to ~nothing in the final build - but MathJax seems like the de facto standard for EPUBs. I'll see if there's anything we can do to trim it down.

[AbeJellinek]

OK, fonts are now loaded on demand and stored as WOFF. Not much of a size improvement, but I think this is as small as it's going to get.