dsh-conversation-rewind: Same-Session Branching and Historical Message Editing for DSH Web

dsh-conversation-rewind is a DSH Web plugin designed to address the need for regenerating AI replies after modifying historical user messages, while maintaining session continuity. This plugin creates an append-only conversation branch within the same session to prevent the creation of new sub-sessions or the loss of the original path. Core functions include: 1. **Inline Editing**: Users can directly modify specific messages in completed conversations; upon confirmation, the conversation branch is created, and replies are regenerated. 2. **Branch Tree Browsing**: Provides a visual tree of branches, supporting read-only browsing of different branch paths without triggering model calls or write operations. 3. **Security Mechanism**: Maintains a persistent event log in an append-only manner using replacement markers.