DeepSeek Harness Plugin: localsummer/dsh-group-chat

The `localsummer/dsh-group-chat` plugin provides DSH with a multi-model, role-based group chat panel, supporting different roles bound to different models and shared context. It allows creating groups and sessions, managing role configurations (such as persona, temperature, and deep thinking), and enables multi-turn conversations with streaming output. Users can use Markdown rendering, image input, and file workspace tools. Data is stored in `~/.dsh/storages/group-chat/`, with support for backup and recovery from corruption.