Maps look blurry at 240x240 and above; how large of a canvas can we get away with cross-browser?

[shannonturner]

In snapCanvasToGrid(), setting MAX_CANVAS_SIZE to 7200 gives a beautifully sharp map even at 360x360.

But not all browsers (notably Safari) could handle it, at least as of a few years ago, and suffered degraded performance or even crashes (especially on mobile).

It would be nice to review and test what the current limitations are, in order to have sharper-looking maps while editing.