dsh-agent-plugin-research: Agent-Specific Plugin Research and Installation Tool Bridge for DeepSeek Harness

`dsh-agent-plugin-research` is an agent-specific plugin tool bridge for DeepSeek Harness (DSH), designed to address the complex origins of community plugins and the difficulty of controlling associated risks. It provides retrieval, auditing, installation, and verification capabilities, and ensures secure, manageable plugin installation through enforced version pinning, risk checks, and an explicit confirmation mechanism. It does not provide a visual interface; instead, it serves as a backend capability to assist agents in plugin management, ultimately helping agents reduce third-party risks when extending their capabilities.