Ref T4900. Broadly, workboard state management is fairly ad-hoc now, which makes things like this (where some kind of edit affects global state) difficult:
- Updating points header to reflect a sum change after dragging a task.
- Changing progress bars after editing a task to change resolution or points value.
- Moving a card to the correct column after editing it and changing subprojects/iterations.
- Responding to real-time notifications about other users moving cards.
This begins rewriting the code in a way that can better accommodate these kinds of far-reaching state update.
This change just moves cover image stuff. I'll continue moving features one at a time until boards work better.