A recent New York Times article about East Coast clam culture got me wondering: Why no clam shacks around Puget Sound? Day-trip to a beach near New York City or Boston or anywhere along the Jersey Shore and you're bound to stumble on a weathered, low-slung joint where the beer is cold and the clams are fresh. Near Seattle? Not so much. And please, don't try to sell me on Ivar's. The sad truth is