Npm update everything except next.js and bulma

[joshka]

This gives a good base of npm packages to work with when updating next.js and avoids any potential incompatible versions during the update.

Bulma is a little more complex to update as it has a variety of interesting changes in the 0.8 -> 1.x update.

Next.js has 2 versions to update (14 and 15).

• use next/font instead of @next/font
• npm bump classnames
• npm bump glob
• npm bump highlight.js
• npm bump react and react-dom
• npm bump rehype-highlight, rehype-raw and add lowlight
• npm bump rehype-slug
• npm bump rehype-stringify, remark{-parse,-rehype}, unified{,-stream}
• npm bump unist-util-visit
• npm bump dev dependencies
• npm bump sass

Testing: I upgraded each dependency individually, checked their changelogs / releases / commits for breaking changes, and compared the output of tokio.rs and localhost:3000 when rendering the same pages.