The Footbridge Mansion, a piece of Tribeca history on one of the city’s most-photographed streets, is back on the market for $29.99 million — a relative bargain, considering it asked $50 million a decade ago. The 8,300-square-foot listing at 9 Jay St. comes with one bedroom and four baths — across two buildings connected by the famed Staple Street skybridge. The assemblage last traded for $24 million in 2022 , Gimme Shelter previously reported. The 118-year-old bridge, which picturesquely