There's no way we can advise you since we can't examine the fork and have no basis for assessing the impact energy. If the shop who saw the entire bike felt the fork was OK, it's hard to overrule them. BTW- t]did they remove the fork and examine it completely including the steerer? Did they also examine the frame, especially the area under the front end of the downtube.

Unfortunately carbon has zero ductility, and so doesn't bend and show damage the way a metal frame would. It's sort of digital, it either looks (and probably is) perfect, or it's obviously broken. If I were riding the bike I might have some idea of the energy involved and would make a decision, but nothing is certain so for anything more than a very light impact (less than the typical deep pothole), I'd replace it based on my likelihood/consequences assessment.

My thinking is that I'm willing to accept a relatively high risk of failure if the consequences are minor, but my risk tolerance devreases as the possible consequences get more severe. Since the possible consequences of a fork failure, especially a base of steerer failure, are off the top of the chart (possible death is not just legal boilerplate), my risk tolerance would approach zero, and if I had any loss if faith in the fork, I'd replace it.

Another way to think about it is would you trust the fork on a high speed descent, maybe on a somewhat bumpy road? If not, there's no way you can enjoy the bike, and have a sense of comfort, so it has to go, even if it seems OK.