A recent tour of the nearly finished South Station Tower, Boston’s newest skyscraper, shows its Ritz-Carlton Residences are all-but-finished and ready to welcome tenants. A quarter-century in the making, the tower offers condos for starting at $1.3 million for a 683-square-foot “junior one-bedroom” and listed as high as $14 million for a duplex penthouse—and for that price, residents will also get a private park, a 25‑meter outdoor pool, library, chef’s kitchen, and a sports simulator room. Take