Show or hide metadata in fullscreen image mode

[jtreminio]

CleanShot.2025-11-22.at.19.23.02.webm

I know in the Discord I showed the metadata container shrinking and expanding dynamically based on user zoom action. However, I went this route because the logic to correctly handle when to minimize, when to zoom back out, how to juggle three different possible user settings (as-is, on zoom, on click) started creating a larger PR than I was comfortable submitting.

This PR is simple: you click the ⇓ button and the metadata is minimized. You click the ⇑ button and the metadata is maximized.

There's a user setting to set the default behavior, but here's the rub: because a modal is actually closed when switching images (particularly from the history container) and immediately reopened to show another image when you're cycling using left/right arrow keys, I had to decide if I wanted to always reapply the user setting on every image switch (boo!), or keep the setting from the last image that was viewed.

However, because it's a bit difficult to tell when the modal was closed by the user clicking to explicitly close the modal, or the modal was closed as part of the close/reopen cycle of the history container, right now the last image viewed setting will apply even when you close the modal and reopen it yourself.

So basically the user setting is useless. I've left it in there in case you have some suggestions on how to get around the issue above, or we can remove it and simply operate using the button and keep the last saved setting. The setting does reset back on page refresh, but that's not really all that valuable right now, it's just a simple button press to hide the metadata.

[jtreminio]

See #974