dsh-group-chat: Start a multi-AI group chat in DSH

# Introduction The philosophy of DSH is "Everything is a Plugin," and many WebUI capabilities are injected via plugins. In agent development, a common requirement is to have several models discuss around the same context in turns—one proposes a solution, one critiques it, and one summarizes it. Without specialized tools, context usually has to be manually moved between multiple sessions, and the speaking order must be monitored manually. The `dsh-group-chat` introduced below turns this into a group chat format: you act as the "group owner" in the DSH WebUI, manage a set of configurable AI roles, and enable them to take turns speaking around a shared context. The plugin is maintained by Qx002, and the current version is 0.1.0. # What is this dsh-group-chat is a DSH native...