The tricky part here was that `returnPartialData` seems to behave differently during SSR. On the page itself, this seems to cause us to always get back at least an empty object, but in SSR we can sometimes get null—which means that a LOT of code that expects the item object to exist while in loading state gets thrown off.
To keep this situation maximally clear, I added a bunch of null handling with `?.` to `ItemPageLayout`. An alternative would have been to check for null and put in an empty object if not, but this feels more resilient and more true to the situation.
The search bar here is a bit tricky, but is pretty straightforwardly adapted from how we did the layouts in App.js. Fingers crossed that it works as smoothly as expected when the search page is migrated too! (Right now typing in there is all messy because it hops over to the fallback route and does its whole separate thing.)
The first page moved over! Note that this broke navigation on the rest of the app, so don't deploy this until we're done!
The reason it broke was that we had to migrate GlobalHeader and GlobalFooter to the Next.js link & router stuff too, or else it crashed because it wasn't in a react-router-dom context.
notable layout change is that the text content will now try to center itself, and we push the buttons off to the right. we also needed to tweak the layout code a bit to get the buttons to feel centered with the top two lines, bc centering against the full block just feels wrong, they want to be top-y in terms of positioning, but still feel centered-y in terms of visual balance
