As Apple Inc. absorbs the regulatory body blow of a record $1.95 billion antitrust fine from the European Union on Monday, its legal team is bracing for yet another epochal action.The U.S. Department of Justice is in the final stages of a yearslong investigation into Apple AAPL, -2.81%, which could lead to a lawsuit as soon as this month. The probe — which reportedly focuses on everything from the seamless integration between the iPhone and Apple Watch, to the company’s digital-payments system and its use o ...