DeepSeek Harness Plugin: dsh-openai-responses-bridge

`dsh-openai-responses-bridge` is a standalone DSH plugin that extends third-party model integration via the OpenAI Responses or Gemini protocol without requiring source code modifications. Core features include model discovery, protocol routing, hosted search tool display, secure credential storage, and hot reloading. The plugin supports native Gemini, reuses native logic, and is compatible with Code Mode/PTC, while not containing plaintext keys. Installation requires DSH version 0.1.2-alpha.2.