- 新增 chatlog 模块、AnalyticalDB 公共层与 common-mq Redis Streams 实现 - 建立 Redis 热态、MySQL 热数据、AnalyticalDB 历史查询与同步链路 - 收紧聊天记录幂等、摘要时序与持久化失败语义
- make chat SSE timeout configurable and default to 10 minutes - stop upstream stream client when emitter send fails - add full exception logging and frontend error notification on stream failures