Port 7 new blog posts from external sources

[cwickham]

New blog posts have appeared in external source repos since the last porting pass. Here's what needs to be ported:

Tidyverse (2 posts)

• orbital-0-5-0 — top-level post in tidyverse.org/content/blog/
• tabpfn-cran — top-level post in tidyverse.org/content/blog/

Positron (2 posts)

• 2026-03-12-notebooks-march-announcement
• 2026-03-31-python-type-checkers

Quarto (2 posts)

• 2026-03-24-1.9-release
• 2026-03-31-typst-books-and-more

Shiny (1 post)

• shiny-python-1.6

Sources confirmed up to date (no new posts)

AI Blog, Great-Tables, Pointblank, Plotnine, Education, RStudio.com