cite-this: a build-time “how to cite” control for Quarto books and websites

I just released cite-this, a Quarto extension that gives readers a “how to cite” control for the current page or for the whole publication, in one click. It copies the citation as text formatted by a CSL style or as a BibTeX @misc entry, and it can also offer the .bib file for download.
What sets it apart is that every citation is prepared during the Quarto render, in Lua. The browser never formats a citation — it only picks which ready-made variant to copy. Because of that the extension needs no client-side citation library, works with embed-resources: true, and still shows a correct citation when JavaScript is disabled. The control is collapsed by default and expands on hover, keyboard focus, or tap, so keyboard and touch users can reach it too.
It ships with seven CSL styles (ABNT, APA, Chicago, Harvard, IEEE, MLA and Vancouver), accepts your own .csl files, reads the metadata your project already declares (title, author, date, site-url), and can be placed in the title, navbar, either sidebar, or a floating corner. Interface text is translated to English, Portuguese and Spanish. There is a live demo and documentation with every position and scope working on the page.