CANNES, France — The Gulf ceasefire lasted barely three weeks. After Iran attacked three commercial ships in the Strait of Hormuz, the United States struck more than 80 targets, revoked Iran’s oil-sanctions waiver​ and declared their memorandum of understanding (MOU) “over.” Yet the market response was telling: Brent crude rose to around $79 per barrel — a meaningful jump, but far below April’s $120 peak, when the strait was closed outright.