Drag-and-drop operations on workboards which edit cards (e.g. in the priority view, and in the future on the assigned view) should put an overlay on the card previewing the operation.

For example, this might look like this:

• Fade the card a bit or whatever.
• Put [Move and reassign to @alincoln] as a tooltip/overlay.

This would make the edit behaviors more predictable, and the multiple different drag modes (T10334) more discoverable/understandable.