Amidst continuing partisan furor, Hollywood producer Rob Reiner today resigned his seat on a state commission he helped found, and was replaced by another Democrat. Gov. Arnold Schwarzenegger praised Reiner's service while accepting the resignation, which Reiner two weeks ago said he would not submit. Schwarzenegger named Hector Ramirez, 38, of La Mirada, as Reiner's successor. Republican state senators had campaigned against the noted liberal Reiner, accusing him of abusing his position as chairman of the First 5 California Children and Families Commission to further passage of Proposition 82, an initiative on the June ballot that would create universal preschool....