By Nidal al-Mughrabi and Fadi Shana CAIRO/GAZA (Reuters) -A U.S. security envoy discussed with Israeli officials on Thursday how to better protect civilians during their war against Hamas in Gaza and President Joe Biden appealed for lives in the Palestinian territory to be saved. Israel pounded the 25-mile (40-kilometer) length of Gaza, killing families in their homes as the more than two-month-old conflict raged across the entire enclave, causing a humanitarian catastrophe with little end in sight. “It will last more than several months – but we will win and we will destroy them,” Israeli Def…