The old URLs were glitchy because we weren't escaping the `layerUrls` param… and this will let us take better advantage of the same shared caching as other stuff!
Oops, okay, I guess I didn't test the new preview centering stuff with 1200x1200 images, like the Usul's Damask Markings.
Now, I apply a max size to the whole-ass container, and make the parent responsible for centering it.
Boom, pulled some stuff out into util! Now we also have error boundaries in both panels of the wardrobe page.
You can test this one by visiting `/outfits/new?send-test-error-for-sentry`, just like on the home page! Util component for fake errors owo
Oops, it was possible after saving an outfit to get into a state where we would show the `<OutfitThumbnailIfCached />` behind the outfit even after it was saved, and then removing items would look weird until auto-saving caught up.
We had used the `backdrop` property because we wanted smoother partial load-ins, but for now I'm just fixing this by switching it to `placeholder`, which already has the right loading-only behavior.
This was also the only call site for `backdrop`, so I've removed it!
