Follow-up to ea2d98179c
This took a couple of iterations to find something that works without creating update loops, but I think that by automatically informing Grid whenever a layout component is re-rendered, we'll have a much easier time ensuring that our layouts are fully reactive.
Includes the mobile UX optimizations and the tweaks we've made to cut down on wasted space, but does not yet include the change to embed the spotlight tile within the grid.
