Assistant message preceding a blocked Stop-hook turn is not displayed; only the post-hook continuation renders #5506

In a Claude Code session hosted by T3 Code (Nightly) 0.0.31 on macOS (arm64), a Stop hook configured to block with feedback splits a reply across two turns. The client displays only the second, post-hook message; the substantive assistant message sent immediately before the hook fired never appears in the conversation view.

The session transcript JSONL contains both messages with distinct timestamps about a minute apart, confirming Claude Code recorded the first message and the renderer dropped it.

To reproduce: configure any Stop hook that exits non-zero with feedback text (for example a hook that asks the model to add evidence for a claim); ask a question whose answer arrives as a full assistant message; let the hook block the turn; the model then continues with a short follow-up message. Expected: both assistant messages visible in the conversation. Observed: only the post-hook follow-up renders as the reply.

Reading the same transcript with the plain claude CLI shows both messages, which isolates the fault to the client's display layer rather than the harness transcript.