- Rename AgentCfg.SaveSession/FlushSave to Save/Flush for brevity
- Remove restoreLegacySession — all sessions now use multi-agent format
- Pass Save/Flush callbacks to agents in CreateAgent and restore paths
- Add AuditLog fallback warning in NewAgent
When a streaming tool completes, emit a final empty-Content event so the
log handler always closes the markdown source fence. In the handler,
emit [[[end]]] directly instead of a blank line, so the GUI block parser
transitions back to BlockStart regardless of what follows.