Adding layers with small scale values results in absurdly large points

If we add a layer with even small-ish scale values, adding points results in massive circles on the screen (at least in some platforms). We should use canvas minimum and maximum point sizes to prevent this.

No file, test, or entry point is named. Search the repository for layer scale handling and canvas point-size calculations, then reproduce the oversized points on an affected platform. Done means small scale values produce bounded, usable point sizes across the supported platforms.

Written by the indexing model from the issue text.