It only took, oh, 15 years or so, so long that it began to feel like a fable. But Miami Worldcenter's vast and long-delayed "city within a city" is finally rising from the ground just north of downtown. For real. Worldcenter's 60-story, glass-wrapped Paramount luxury condo tower, which sits on a block-long retail and amenity podium, has topped off and will open next year. A stand-alone retail and garage building is under construction across what will be the city's first pedes