add search

Try using https://github.com/mansona/html-extractor to pull out the relevant parts of the HTML from markdown

Then try one of the frontend-only search indexers to load those objects and build an index https://www.npmtrends.com/elasticlunr-vs-fuse.js-vs-fuzzy-vs-fuzzysearch-vs-lunr-vs-reds-vs-search-index

Altenatively we could just do what mdbook is doing: https://github.com/rust-lang/mdBook/blob/a5fddfa4683e45b1ab6d26629670acfcd5b4f18a/src/renderer/html_handlebars/search.rs#L66

> Renders markdown into flat unformatted text and adds it to the search index.

and then we can just use the "flat unformatted text" to feed directly into the index