Very nice work; I've enjoyed using Stellarium several times, in night mode, to find various stars and planets in the sky, and it's wonderful to see a web version now.

I'm curious about something: on your Github project, you mention using a CLA, but it sounds like the only reason you're using it is to ensure provenance and irrevocability of contributions. Given that, have you considered using something like the Developer Certificate of Origin (DCO, AKA "Signed-off-by"), which has built-in support in Git and much broader acceptance in the FOSS community?