dsh-auto-preset-router: DeepSeek Harness Auto-Routing Plugin

`dsh-auto-preset-router` is a DeepSeek Harness plugin designed to solve the pain point of manual intervention when switching presets. It uses the DeepSeek V4 Flash model to automatically detect the intent of a user’s first prompt and route it to a preset such as Standard, Code, Minimal, or Cordis. The plugin uses one classification call to determine the preset and a second call to select the required tools. If classification fails, the system falls back to Standard. It only processes prompt text and attachment metadata, does not send image content, and does not modify the underlying configuration, improving the user experience through intelligent routing.