By Jan Wolfe (Reuters) – The wife of a former U.S. naval engineer pleaded guilty on Friday to helping her husband try to sell secrets about U.S. nuclear submarines to an unknown foreign country. The guilty plea by Diana Toebbe, 46, was part of a deal with prosecutors that calls for her to get a much shorter prison sentence than her husband. Her husband, Jonathan Toebbe, 42, admitted on Monday to conspiring with his wife to disclose restricted data, a violation of the Atomic Energy Act that carries a maximum sentence of life in prison. [nL1N2UP1XA] His plea agreement calls for him to face a lik…