ThinHarness 0.8.0

• Changed OpenAI Responses state to replay the exact raw item history by default with store: false. Use OpenAIResponsesModel(..., state_mode="continuation") to opt into server-managed previous_response_id continuation.
• Breaking: Built-in transcript resume state is now version 5. OpenAI replay state includes exact raw Responses items in openai_items; version 4 state must be regenerated.