R1:7ce8a1f437ae

Turn thumbs into a history grid thing

Summary:
This could probably use some refinement (and, like, explanatory text, and stronger cues about what rows and columns mean) but feels fairly good to me, at least on test data.

I didn't do any scrolling for now since we have to do full height on mobile anyway I think. I did swap it so the newer ones are on top.

Left/right navigate you among current images only, but you can click any thumb to review history.

Removed history view since it's no longer useful.