Prompts sent while a turn is active are queued on the daemon instead of in the browser's React state. The queue is persisted in the session sidecar and drained as the next turn when the current one completes. Fixes the bug where queued messages were delivered to the wrong session when switching focus in the UI: the client-side queue captured the new sessionId in its drain closure. Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>