DeepSeek Harness Key Vault Plugin

`dsh-keyring` is a key management plugin for DeepSeek Harness, designed to mitigate the risk of API key exposure. It supports automatic key masking, centralized storage, and persistent storage across restarts. The plugin provides CLI model tools and a Web UI management interface, with two-level storage at both global and session levels. Developers can use this plugin to securely store, retrieve, and clean up API keys, reducing the risk of leakage during development.