dsh-generate-image: Generate and Edit Images Using Local Codex CLI

The DSH plugin `dsh-generate-image` introduces local visual capabilities for DeepSeek models by leveraging a locally logged-in Codex CLI to perform text-to-image and image-to-image generation. The plugin can be invoked directly through the `generate_image` tool, without requiring an API key or a build step. Generated images are saved in the directory created by Codex. Installation requires a local Codex login and Node.js >= 18, and it can be completed with a single npx command.