Is it a good idea to connect the Neutral point to your common ground in your PCB?
Let me give you the simple answer. No, do not connect any current carrying conductor from AC mains to your low-voltage circuit. Regardless of whether it is "hot" or "neutral". Don't connect it. Some people are suggesting that in some situations you might have to connect it for the power supply to function. If that is the case, do not use that power supply.

Also, you would be better off whether you are a professional or an amateur, if you used external AC-DC converters (agency approved) for all your projects.