Dean G. Skelos, the leader of the New York State Senate, and his son were arrested on Monday by federal authorities on extortion, fraud and bribe solicitation charges, expanding the corruption investigation that has cast a renewed spotlight on Albany’s intractable corruption problem. The charges against Senator Skelos, 67, and his son, Adam B. Skelos, 32, were detailed in a six-count criminal complaint that quickly became mandatory reading material in the Capitol building. Politicians and their staff members pored over the 43-page complaint — an often titillating document that included references to burner phones, secretly taped conversations and strong-arm tactics...