- POST /api/v1/chat 与 ws.chat 上行新增可选 mode(行为模式 design/01 §3/design/16 §5.1) - Web路径经ctx透传本轮mode到编排器持久化(persistUserMessages/persistAssistantReply),缺省回落chat - pendingMsg记录mode,恢复/续接路径沿用发起轮次mode - IM路径(persistToMain/persistIsolated)恒为chat - 新增/扩充测试:REST/WS/orchestrator/channelbridge 覆盖mode写入 - Docs/api-client.md v0.20 同步mode字段