The Forest Hills mom found dead in a hockey duffel bag spent some of her final hours puttering around her yard and enjoying a night out — before video caught a mysterious figure lugging her makeshift casket down the street. Cops are now trying to piece together how Orsolya Gaal, 51, went from a well-to-do, seemingly typical stay-at-home married mom of two to slay victim. “It’s a mystery,” an NYPD official told The Post on Sunday. “Now it’s a question of piecing together everything she did that night.” The source said that during Gaal’s final hours Friday, “She goes out...