Ballots will start to arrive in Sacramento mailboxes next week, including four contenders for mayor. New documents give voters a glimpse into who’s funding their campaigns. California Assemblyman Kevin McCarty has the most cash on hand with $612,992, including some big checks from labor groups, politicians, corporations, and statewide law enforcement groups. Former councilman Steve Hansen, supported by the city police union and the Sacramento Metro Chamber of Commerce, has the second most cash on hand at $235,797. Former state senator Dr. Richard Pan came in third with $124,982. Epidemiologist…