In a darkened stall, Jade Muller reached out and placed her hand on the soft, warm belly of a miniature horse named Precious. Muller was breathing fast and shallow, on the verge of a panic attack. Precious’ side rose and fell much more slowly and Muller struggled to breathe in sync. As the musky smell of the tiny horse filled her nostrils, Muller’s breathing slowed, her anxiety eased. And with that came release. For the first time since she saw the black barrel of a gun poke its way into her freshman English classroom at Marjory Stoneman Douglas High School four years ago, wounding five of her…