Output visualizations to SVG rather than PDF

This all works very nicely until it's time for back-end rendering and/or sanitation. At that point, it becomes a shotgun-wedding to wkhtmltopdf, React server-side rendering, bespoke Node scripts w/ SVG DOM subsitutes, or all of the above.

Nobody's going to notice five more dependencies out of the hundreds already in package.json, and everyone already drank the kool-aid on a gig of RAM and a supercomputer as table-stakes for generating a five-page PDF, so go for it!