On a fence in Rockridge  full-color signs show computer renderings of a two-story shopping complex  anchored by a brand new Safeway The signs—the fence to which they’re affixed surrounds a former Union 76 station that Safeway bought in 2009—are the most visible daily markers of a five year-old conflict over the future of this block between College  Claremont and Alcatraz  at the heart of Rockridge