SANTA CLARA – Brock Purdy got an encouraging pat on his shoulder pads as Sam Darnold said to him: “See ya in a couple of weeks.” For Purdy’s sixth-seeded 49ers to stage a rematch with Darnold’s top-seeded Seahawks, wild-card survival comes first. The 49ers’ postseason “Road Dog Tour” will open at the No. 3-seed Philadelphia Eagles, who won last year’s Super Bowl and who three years ago downed the 49ers and tore Brock Purdy’s elbow ligament in the NFC Championship Game. (Check back for updates on dates and times for the wild-card round). Saturday night, the 49ers lost a shot at the No. 1 seed and home-field advantage through Super Bowl LX by virtue of a 13-3 defeat to the...