Fix mobile viewport by adding Full screen flag.

[develroo]

On mobile devices (Tablets/Phones) the default browsers leave a header bar or footer bar to keep navigation accessible. However, that puts the viewport in an offset mode. This leads to the view port to move when you move a token, as the token will only move when the edge of the view port is reached.

Examples.

Portrait:

recording_20230115_102808.mp4

Landscape

recording_20230115_104705.mp4

This ought to be solved by just specifying the 'Full Screen' flag when rendering for these platforms. It is explained for JavaScript here. Which should apply to all browsers, mobile or not.

https://developer.mozilla.org/en-US/docs/Web/API/Fullscreen_API

You can add a full screen toggle button in the GUI like this.