Jamison “Jamie” Marra, president and CEO of Bellevue-based software development and consulting firm Singularity Partners, and his wife, Shannon Marra, are listing their Medina mansion for $7.56 million. The interior of this traditional home, a mix of classic-modern and vintage, was designed by Nate Berkus, and is the first project in Seattle to have the stamp of this famed philanthropic designer, author and gentle TV personality.