dsh-meeting-coordinator: Equipping Agents with Persistent Meeting Rooms and Mutual Session Wake-up

`dsh-meeting-coordinator` is a plugin in DeepSeek Harness that addresses context contamination and forgetting in long-running multi-agent workflows. Built on the `dsh-std` protocol, it enables structured cross-workspace collaboration by establishing a persistent “meeting room” and membership mechanism. Core features include members proactively joining with pre-injected context, state transitions (working/idle-waiting/done) with emergency stop and session restoration, and a context-free host steering the session. The system ensures stability by enforcing hard budgets on word count and isolating data root directories. It is currently in an early stage and already covers 215 test cases.