I'm running this on codepen.io since it has automatic updates and I don't have to wait for it to update. So I'm not 100% where the error occurs since it gives me a link that returns 404 as the location. According to Gemini, it's line 135, but that doesn't make sense since my lowest line is line 116.
And there is a run animation
In case it matters, when the script is started, the skeleton and atlas are not initially defined, they only are BASE64 encoded and uploaded after the filename constant is defined.