Plugin forwarding reports "not confirmed", and two dialogs get readable names

Three small user-visible additions. Cloud plugin forwarding now says "sent, not confirmed by the session" when the session never reported back a loaded plugin count, where it previously reported nothing at all. Peer tool-call failures gain the classifier-refusal reason. And two pending dialogs now show a label instead of a blank: iTerm2 setup reads "choose: install the iTerm2 integration or use tmux", and computer-use approval reads "choose: allow or deny the computer-use action".