Selena Gomez is poised to star in STXfilms' psychological horror-thriller Dollhouse, which she has just signed on to produce under her July Moon Productions banner along with Shawn Levy and his company 21 Laps. Michael Paisley wrote the script, and while plot details are being kept in a tiny room somewhere, the project is set in the upper echelon of New York City’s fashion scene, and said to be in the vein of Black Swan. It will be developed as a starring vehicle for Gomez. 21 Laps' Dan Cohen will join Levy and Gomez in producing the film, …