dsh-plugin-sirchmunk: Native DSH Sirchmunk Configuration and Monitoring Plugin

The native Web plugin `dsh-plugin-sirchmunk` for DeepSeek Harness (DSH), built on the core design philosophy of “everything is a plugin,” introduces a centralized management area named Sirchmunk into the DSH settings interface. It primarily provides knowledge graph visualization and export, cluster management (including permission control), runtime monitoring, shared history tracking, and de-identification of privacy data. In addition, it includes a built-in Agent Skill named `sirchmunk-search`, which supports searching local documents in over 100 formats via MCP tools. Implemented using a Host/Client architecture, the plugin relies on a local Sirchmunk service and takes effect after restarting the DSH host once installed.