Stick a fork in ’em? The Nationals’ three game cross-country trip to San Diego, which started out on a high note with Friday night’s 5-1 victory (John Patterson was brilliant – 9IP, 3H, 0BB, 1R, 6K), ended in the worst way possible: back-to-back heartbreaking losses that might have finally, quietly, snuffed out their 2005 playoff hopes. As you remember, the banged-up Nats left for the West Coast on Thursday a giddy bunch, with their…