- Preserve streamed assistant text in Desktop UI when message.complete delivers empty text.
- Prevent destructive hydration in Desktop useMessageStream over rendered text on empty completion.
- Recover stream buffer in finalize_turn when final_response is empty on healthy turns.
- Unify in-place blank assistant repair, watermark clone resolution, non-blank concurrent winner adoption, and batch row appends into a single atomic guarded SessionDB transaction.
- Synchronize canonical committed content to live in-memory messages dicts and preserve all-or-nothing rollback semantics on persistence failure.