Developer Related Companies has agreed to build a more than $7 billion data-center, one of the largest deals yet for this burgeoning real estate class that powers AI. Related’s 250-acre campus in Saline Township, Mich., is the fourth new site announced as part of a $300-billion contract signed between Oracle and OpenAI, which the ChatGPT maker says is part of its larger Stargate project designed to build trillions of dollars worth of new computing capacity.