U.S. shale oil producers are boosting output in response to the energy crunch caused by the war in the Middle East. Exports are running at all-time highs. The media are celebrating the country’s energy dominance. But there are limits to what the U.S. energy industry can do and how long it can keep doing it. Drillers across the shale patch have been adding rigs again in what is an obvious sign of changing sentiment in an industry that has focused on caution and capital discipline for years now. But with the U.S.-Iran war driving benchmarks…