In a city that changes faster than a Midtown rent hike , some New Yorkers are doing the unthinkable: hitting pause — on the present. From Jazz Age cocktail bars to punk-rock basements that still smell like hairspray and rebellion , a growing set of young New Yorkers are spending their weekends time-traveling through the five boroughs — no flux capacitor required. The inspiration? TikTok creator Dasha Kofman, whose nostalgic “day in the decade” videos have turned NYC into a living, breathing time machine. “I’m on a mission to spend a day in New York City like all the decades. Here’s how you could do it as if you were in the 1950s and ’60s,” the 29-year-old says in one viral video. She adds that the idea is to “start each day the way New Yorkers would’ve in the mid-century,” before heading to a famous “Goodfellas” filming spot and calling Jackson Hole Diner one of the only places in the city that truly captures the era.…