It would still be obvious by distinct posting/submission patterns and a nonzero chance of its output being incorrect hallucinations. AI agents aren't AGI.
No, and very very few Hacker News users would be interested in that because people have tried that since the rise of ChatGPT years ago and they are all slop.
Don't pursue this or anything related to an AI news aggregator, it's both a) ineffective and a waste of time for everyone involved and b) everyone has tried doing it before, which is how we know a).