ABDI SHEIKH  MOGADISHU is a city of ruined glory: crenellated towers crumble by the sea and sand whirls against the pockmarked archways of the roofless old cathedral. But one young man, returning to his family's homeland, walks through the streets and dreams of their future. Omar Degan, 30, was born in Italy to Somali parents who left three years before civil war broke out in 1991. He studied architecture in Italy and Hong Kong before returning to Mogadishu in 2017, part of an influx of young diaspora Somalis returning to rebuild their country. "I feel extremely sad and angry when…