CAIRO — Egypt’s military government is sharply expanding emergency powers to detain people without evidence or official charges, in what critics are decrying as the most significant curbs on personal freedoms here since the fall of Hosni Mubarak. In the wake of the mob assault on the Israeli Embassy last week, Egypt’s interim leaders are reviving and broadening laws used to detain thousands of dissidents during the Mubarak years, calling the move critical to maintaining law and order in a country confronting a tumultuous transition to democracy.