Foreign ministers from Cambodia and Thailand convened with their Chinese counterpart on Monday as the Beijing government, building on its expanding presence in the world diplomatic arena, sought to play a stronger mediating role in the violent border dispute between the two Southeast Asian countries.The trilateral meeting, held in a southwestern Chinese province north of the contested border, came two days after Thailand and Cambodia signed a fresh ceasefire agreement to end weeks of fighting that killed more than 100 people and forced hundreds of thousands to be evacuated on both sides of the border.Chinese Foreign Minister Wang Yi called...