/btw continue flow loses previous conversation context

Summary

Fixed in PR #187.

Problem: When using the /btw conversation flow and then asking a follow-up question, the assistant behaved as if the previous conversation did not exist.

Root Cause: In persist_btw_turn method, when a /btw conversation completed, although DialogTurnData was saved to persistence layer, the messages were not synced to the in-memory caches (MessageHistoryManager and CompressionManager).

Fix: After persisting the turn to disk, now sync the user message and assistant response to both memory caches.