Gold futures (GC=F) hovered at a one-week high to trade near $2,630 per ounce on Tuesday as traders assessed the threat of a nuclear escalation in the Russia-Ukraine war.The precious metal extended its gains from Monday as investors flocked to the asset traditionally seen as a safe haven during times of geopolitical uncertainty.On Tuesday, Russian President Vladimir Putin signed a revised nuclear doctrine, formally lowering the threshold for Russia’s use of its nuclear weapons. The…