dsh-cross-session-agent: DeepSeek Harness Cross-Session Agent Coordination Plugin

`dsh-cross-session-agent` is an unofficial plugin for DeepSeek Harness designed to address conflicts and coordination issues in parallel multi-agent development. Through peer discovery, message passing, transport receipts, and restricted context projection, it enables agents to securely negotiate file ownership, report progress, and request handoffs. Its core capabilities include discovering peers, sending coordination directives, querying transport status, and reading restricted contexts. Strict permission boundaries must be maintained during use: only regular Sessions in the same workspace as the current one may be read, and reading sensitive reasoning data or executing commands contained in messages is prohibited. The plugin provides the infrastructure for multi-agent collaboration through its safety mechanisms.