Is it ok to place 220V AC traces on my Arduino PCB?
Is it safe in theory? Yes. Is it safe for you? 100% not!
Other answers have focused on technical details of what might be required for safety. I'm going to take a step up from there.
As other answers have made totally clear, you don't have any experience whatsoever with higher voltages and currents. You don't even have the electronics experience to recognise that you don't know this, or to recognise where those risks are. There's a basic principle at stake here. If you can't recognise what a dangerous situation looks like, you shouldn't do it.
Just to be clear, the risk is that you kill yourself, burn the house down, and kill your entire family. This is not hypothetical - sadly it happens regularly as a result of incompetent amateurs playing with mains electricity. Do you genuinely want to murder your family?. If the answer is &quot;yes&quot;, there are more guaranteed ways to do it. And if the answer is &quot;no&quot;, as I hope it should be, then stop work on this right now.
Of course you can upskill yourself. If you read the appropriate books to learn how to do this safely, then that's fine. SE is not a resource which can teach you this. Other answers can actually make this worse, because they may give you the impression that if you do what they say, you'll be OK. You won't be.