BRUSSELS — The European Union published on Thursday a list of U.S. imports that it would target with retaliatory duties if no solution is found to end President Trump’s tariff war, which could include aircraft maker Boeing. At the same time, the EU’s executive branch, the European Commission, said that it would begin legal action at the World Trade Organization over the “reciprocal tariffs” that Trump imposed on countries around the world a month ago. “The EU remains fully committed to finding negotiated outcomes with the U.S.,” commission President Ursula von der Leyen said. “At the same time, we continue...