Sharon Greytak’s “Archaeology of a Woman,” now playing in New York, is a scintillating, intimate look at the horrors of dementia crossed with a purposefully disorienting murder mystery. Margaret (Sally Kirkland in riveting form) is a septuagenarian prone to automotive scrapes and violent temper tantrums. Her fortysomething daughter Kate (an equally fine Victoria Clark) is understandably worried after the police begin calling her