- Updated the design document to reflect the final version, incorporating multi-model support and enhanced version management features.
- Expanded the data structure section to include new entities and relationships, such as `askId`, `parentMessageId`, and `siblingIds`.
- Improved the core operation processes, including sending new messages and managing message versions.
- Added detailed diagrams and performance analysis to illustrate the new architecture and its advantages over the previous system.
- Ensured backward compatibility while introducing new functionalities for branching conversations and version control.
- Introduced a comprehensive design document outlining the architecture and requirements for a message history version management system.
- Added new entities `UserMessage` and `AssistantMessageGroup` to support a directed multi-branch conversation structure and version management.
- Updated existing entities to accommodate the new architecture while maintaining backward compatibility.
- Included performance analysis and migration strategies for transitioning to the new system.
