RelayLoom: Provides a default-off DingTalk Stream session relay for DSH

RelayLoom is an independent, opt-in external chat relay plugin designed for DeepSeek Harness (DSH) to securely deliver DSH agent responses to users via the DingTalk Stream protocol. Licensed under the MIT license, the plugin requires a Node.js 22.19+ environment and has no official affiliation with DingTalk or DeepSeek. Its core features include sending ACKs immediately before asynchronous work completes, deduplicating retries based on msgId, and limiting memory usage; it supports filtering private and group mentions, implements a default deny policy (default-deny) and a staff-id-based allow list to ensure session isolation; and provides `/approve` and `/reject`.