I was rereading ASoS last week and noticed for the first time that Jaime's dream happened on a weirwood stump. I don't think it is prophetic of his death as much as her being a chance of salvation. She is the only thing that is from the present and his future while his attackers are from his past. I think it was arleady fulfilled in a way when he sent her to keep his word. The other ghosts he confronts are all people he let down or saw him in a dishonorable light, and him offering to fight against them was a continuation of his arrogance. Asking her for help, was him breaking the cycle.