Improve Visuals for Pinned Items

[ben-miles]

While in the "Items" view, there's no visual indication that an item has been added to the "List" view. Some kind of persistent highlight color or icon would solve that.

It'd also be good to add some "gesture" toward the nav button for the "Items" view; just to remind the user where the pinned items can then be found. Ideally, a very brief "flash" of color or some other highlight on the nav button itself, triggered every time an item is added.