I don't have an answer about the stage when something should be considered authored by AI - we are in an uncharted territory on this.
There are some precedents and rulings related to copyright and AI, so we have at least some rubric by which "authorship" can be determined. But when it comes to AI doing polishing of existing code - that is less certain.
There are some precedents and rulings related to copyright and AI, so we have at least some rubric by which "authorship" can be determined. But when it comes to AI doing polishing of existing code - that is less certain.