Lots of updates. I tried to keep them pretty contained into individual commits except for the second-to-last one where I was just dumping all of the edits into a large cleanup commit.

Basic rundown of stuff:

• Update all dependencies to latest (it still works, so yay)
• Set minimum Node.js to latest (v22) -- v16 reached end-of-life a couple of years ago.
• Resolved all Gatsby deprecation warnings (except for Gatsby Head, which is a whole effort on its own)
• Replaced deprecated Gatsby plugins -- there has been a change to its image processor which no longer allows for traced SVG placeholders, but these are not critical
• Migrated eslint configuration
• Resolved a large handful of annoying eslint warnings (e.g. they wanted functions written in a particular format) and turned some off. I didn't actually run eslint across the entire codebase though, that's an exercise for some future thing
• Removed defaultProps in favor of default variables because React was warning this would be deprecated in future (and honestly I feel prop-types should be replaced by TypeScript, eventually)
• Refactored the way props were spread through components to prevent props from accidentally turning into HTML attributes (if you looked in the rendered source you'd see things like <span conditions="[object Object"]>, which ugh)
• Similarly -- props that controlled styled components would become HTML attributes, this can be resolved by naming props with a $, e.g. isActive={true} --> $isActive={true}
• Other small bug fixes, like arrays of React components not having the correct keys