Okay, so I still don't know why rendering is just so slow (though
migrating away from item translations did help!), but I can at least
cache entire closet lists as a basic measure.
That way, the first user to see the latest version of a closet list
will still need just as much time to load it… but *only* the ones that
have changed since last time (rather than always the full page), and
then subsequent users get to reuse it too!
Should help a lot for high-traffic lists, which incidentally are likely
to be the big ones belonging to highly active traders!
One big change we needed to make was to extract the `user-owns` and
`user-wants` classes (which we use for trade matches for *the user
viewing the list right now*) out of the cached HTML, and apply them
after with Javascript instead. I always dislike moving stuff to JS, but
the wins here seem. truly very very good, all things considered!
From an era when we didn't have that! Now we do!
(My motivation is that I'm trying to add new JS to this page and errors
in stickUp are crashing the page early, womp womp!)
We lose no-JS support, which I kinda miss, but caching is gonna be more
important down the line. Delete form moves next, then we cache.
CSRF token changes: it looks like, by setting a data attribute in AJAX, I
was overwriting the CSRF token. I don't remember it working that way, but
now we use beforeSend to add the X-CSRF-Token header instead, which is nicer,
anyway. The issue might've been something else, but this worked :/
The CSS was also not showing the loading ellipsis properly. I think that's a
dev-only issue in how live assets are being served versus static assets, but
may as well add UTF-8 charset directives everywhere, anyway.
