First Lady Tammy Murphy, who has her eyes set on a U.S. Senate seat, did not mince words Tuesday when she denounced a much-maligned proposal — that her husband has supported— to add a fourth gas-fired power plant in Newark. “Today I stand before you (and) I believe with all of my heart that given … this part of our state already has three gas burning power plants. It already has the largest incinerator … I stand strongly with you, I oppose the PVSC plant in this space,” Murphy, the wife of Gov. Phil Murphy, said of a project her husband’s administration has kept on the table and remains un…