NAHARIYA, Israel — Israel said Sunday its military was conducting a “large-scale operation” to locate the last hostage in Gaza, as Washington and other mediators pressure Israel and Hamas to move into the next phase of their ceasefire . The statement came as Israel’s Cabinet met to discuss the possibility of opening Gaza’s key Rafah border crossing with Egypt, and a day after top U.S. envoys met with Prime Minister Benjamin Netanyahu about next steps. The return of the remaining hostage, Ran