If you find yourself in Montauk this September, The Surf Lodge’s The Sanctuary is holding space for your — and  your gym bag’s — wellbeing… Montauk, in spite of its growing incantation as a thriving summer mecca, remains peaceful at heart — accepting and resilient, and quick to revert into a sleepy sort of existence once the annual migration of city folk subsides. “The End,” nicknamed that because Montauk sits at the literal end of Long Island, beckons people to…