A federal judge declined to dismiss charges, but set a trial date for a year from now in the case against a retired homicide detective from Sand Canyon accused of being part of an extortion ring. Federal prosecutors alleged Steven Arthur Lankford, 68, was part of a crew that tried to bully an Irvine man into signing away his multimillion-dollar interest in a company he shared with a Chinese national, a man accused of financing a sham raid against the victim. At Lankford’s most recent hearing, Judge Wesley L. Hsu denied a motion to dismiss the charges against Lankford, which included four counts alleging conspiracy to…