Venus Cloud City One: Passage

Humanity was building a quantum communication relay station in the Cloud City of Venus, and accidentally hit a stable wormhole. The other end was connected to an equally habitable gas giant planet 250,000 light-years away. There is already an ancient civilization up there, and they are also looking for neighbors. Two civilizations started trade 250,000 light-years apart - you are the "Channel Administrator", responsible for exchanging information and materials. Until one day, the other party tells you: We have detected that your Venus habitable zone is somewhere...