carry_unadmitted_user_message appends the interrupted turn's user row to the
early result's in-memory history only; it is never persisted because that turn
never owned the lease. When the follow-up turn also has to wait for the lease
(the common case: the other process that made the first turn wait is usually
still busy), admit_durable_turn_lease reloads conversation_history from the DB
after admission and replaced the caller's list wholesale, so the tagged row was
dropped from both the model input and state.db. Re-append the tagged rows that
have no _row_id after the reload so the follow-up turn sees and flushes them.
Review finding: waited-reload branch of admit_durable_turn_lease discarded the
_persist_after_admission_interrupt row carried from the aborted turn.
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