At the narrow throat of the Persian Gulf, where a third of the world's seaborne oil passes through waters both nations claim to govern, Iran and Oman have proposed a temporary shipping corridor through the Strait of Hormuz — a diplomatic gesture born of weeks of negotiation and shaped by the mounting pressure of American sanctions. The agreement, announced Tuesday after talks between the two countries' foreign ministers in Tehran, envisions joint demining operations and a phased path toward a permanent arrangement. Yet the proposal lands in contested terrain: Washington insists the strait is i