PHOTO COURTESY OF ALLY RUSSELL It’s August, but author Ally Russell is in an autumnal mood. Writing spooky stories and sipping cocoa at her desk while a black cat purrs on the window sill helps create the illusion that it’s mid-October and not a sweltering summer day. The 39-year-old currently resides in Bellefonte, Pa. — home of Big Spring Spirits, a distillery with a local site on the South Shore — but she grew up reading “Goosebumps” and wat…