Key-convention policy, settled: every field accepts ⌘/Ctrl+Enter (metaKey || ctrlKey — Mac gets ⌘↵, Windows/Linux Ctrl↵, the Gmail convention); plain Enter stays matched to the field's species — sends in message fields (chat composer, free-text answers — the universal chat convention, Shift+Enter still a newline), newline in the thinking field (composition, for dumping).