Is there a website or R function that can help us answer the question "has this particular person authored any CRAN packages"? Turns out, no.

This question was asked a decade ago on StackOverflow, and for a while the p_search_any() function of the pacman package seems to have done the job. But since at least 2018 this function no longer works (likely because CRAN changed its website HTML).
It is unfortunate that the pacman documentation still describes this function, which I imagine might confuse any would-be users.

CRAN does list all package maintainers in a simple (but quite large) HTML table, but that is not the same as authors.

The more modern pkgsearch package does not offer any way to search by authors, as far as I can tell.

I am not sure whether other repositories (TeXLive, for example) offer a simple way to search by authors. But as demonstrated by pacman this is doable via web scraping, but as scraping is inherently fragile ideally CRAN should offer the data in some structured format (JSON, XML, whatever). If we are wishing for stuff anyway, I would also like to add that it would be awesome to search not just using name but also ORCID.