weichen
3b92cb63b4
Why: Interleaved-thinking models (MiniMax, DeepSeek R1) require the assistant's thinking to be passed back verbatim in message history; dropping it degrades later turns. The product's P2-I1 replayed thinking only into the request-side rebuild; with the session transcript becoming the authoritative context (quality P2-I2), capture must live in the kernel so thinking persists in the transcript and replays on every request. Evidence: SELF - TestReasoningCaptureAndReplay covers capture (SSE reasoning_content into Message.Thinking, content unpolluted) and replay (<think> prefix on thinking assistants, untouched non-thinking messages); go vet + go test ./... pass. Impact: sse.go accumulates reasoning deltas into the terminal message's Thinking; client.go toProviderMessages renders captured thinking as a <think> block prefix for assistant messages. Anthropic path unchanged; messages without thinking serialize exactly as before.