I'm currently getting this error:

[Copilot.lua] RPC[Error] code_name = unknown, code = 1000, message = "Not authenticated: Failed to get copilot token due to 401 status. Please sign out and try again."

I tried :Copilot auth but it says I'm already authenticated.

There is no command that I can see that allows me to log out.

Also, commands should be documented somewhere. Either in the README or at the top of :he copilot.lua