The sentences that say "run" are incorrect because "run" is present tense. "ran" is correct because it is paste tense. "You just ran a stop sign." and "You just ran a red light." are correct. You can also say, "You just ran through a red light." I don't think "You just ran through a stop sign" would work because it gives the literal mental image of crashing a car through a stop sign, not driving past it.