Well the alien that Arroway meets on the beach says that they didn't create the worm holes, they found them, but have never found the creators, iirc. I just re read some of the parts that mention pi, and I was remembering it wrong. She goes looking for a picture, but I'm not sure she finds anything by the end of the book. I'm going to re read the whole book this weekend, it has been too long. Thanks for having a look!
So to your question, I think the book says that yes, either the universe was created with this cool egg in pi as a message for civilizations to find once the got computers that were good enough to scan for statistical anomalies 2*20 digits deep in pi, or else the egg was somehow hacked into it some time after creation.