Media startup Run-A-Muck is going all in on short stories.   The company, co-founded by Condé Nast alum Pamela Drucker Mann, is set to launch short stories on its ad-supported culture and fashion Substack, Drafting, according to a report from The Wall Street Journal.   The move comes along with the company’s bet that the material could be the next major source of intellectual property for film, television, podcasts and other multimedia projects. They plan to adapt successful works across multiple platforms.   “Rather than starting with a medium and searching for an audience, we start with the story we want to tell and then determine the format that best serves that story,” Drucker Mann told WSJ.   Several notable writers have already signed up to publish on the platform. Among them are Cody Behan — writer of short story “The Decorator,” which is set to be adapted for Netflix — and Abbott Elementary writer and director Brittani Nichols.  Adaptation is not the entire goal of the push into shorter fiction, however. Some stories posted on the platform will simply remain in that form. “Not everything we create is destined to become a television series or feature film,” Drucker Mann added.   Drafting, Run-A-Muck’s seven-month-old Substack publication, attracts more than 50,000 monthly readers. Hermès, Moncler and eBay are reportedly among the publication’s advertisers — former Wondery and Google sales …