Don't be afraid, and enjoy your time in Poland with the family. Most military activity (weapon transports, etc.) is happening in Rzeszów, which is more than 500km from Gdańsk in a straight line. As of now, Poland seems to be disarmed by helping the Ukraine, so I guess there are PR campaigns in the media to create appearances, and nobody, even crazies in Poland, wants any open conflict. Gdańsk is also too precious for anyone to destroy it. It's a hub that might play a role in connecting the Black Sea with the Baltic Sea, so I doubt that anyone will try to damage the infrastructure. So I'd say it could be one of the safest places to be in Poland.