Every summer writers of all stripes - poets, novelists, screenwriters and writers of memoirs, histories, essays and short stories - descend on Squaw Valley for a week of intensive literary activity. The valley buzzes with metaphors flying and manuscripts flapping, as more than 250 writers, editors and publishers convene in two separate week-long workshops in poetry, fiction, nonfiction, memoir and screenwriting.The Community of Writers at Squaw Valley invites the public to attend the dozens of literary events and readings taking place as part of its Writers Workshops today through July 14. Schedule for Sunday, 8 p.m. Reading, book signing and …