A dream long nurtured by grassroots neighborhood activists approached reality last week when Gov. Andrew Cuomo announced an offshore wind turbine assembly hub in Brooklyn — part of a promised “green energy economy.” Sunset Park environmental justice advocates had pressed for more than two decades to revive a declining industrial waterfront while sowing the seeds for projects that would serve their largely Latino and immigrant community as well as the environment. “The possibility of bringing good paying jobs to our community and to also address climate change, for us, that’s everything,” said Elizabeth Yeampierre, executive director of the local group UPROSE. “That’s what we fight for. We fight for our people, for our