Kulwinder Singh Soni’s voice quavered as he recounted the day in March 2020 when an Islamic State gunman burst into a Sikh gurdwara’s prayer hall in Kabul, hurling grenades and firing assault rifles. Among the 25 people killed were Soni’s father, sister-in-law and 4-year-old niece. Police later warned the family not to attend their funerals…