Add has_frame properties to Box and Bin

### Problem

Currently we have a Css class for Cards, but we've been moving away from manually adding style classes towards widgets having properties

### Proposal

Maybe it would be nicer if we just added `has_frame` properties to box and bin?

### Prior Art (Optional)

_No response_

Locate the Box and Bin widget definitions and inspect how the existing Cards CSS class provides its frame styling. Compare that behavior with the proposed has_frame properties, then confirm that both widgets expose the property and that their framed appearance matches the existing Cards treatment.

Written by the indexing model from the issue text.