Artefact peaking

[tucnak]

Once the margins are implemented correctly per #17, and we can incorporate #18 as example, peaking behaviour that we'd discussed earlier would need to be introduced. That is, leaving just enough space on mobile for the reduced-size (with the larger tap bounding box) artefact to be accessible as entry-point for swiping UX.

The provisioning of artefact viewport component is beyond the scope of this issue.

[sh-0ut]

When printing, the artefact qr component ‘hides’ outside the screen

[tucnak]

This is got to be classed as bug now.