codex-plugin-dsh: Using Native Codex as a Local Provider in DeepSeek Harness

`codex-plugin-dsh` is an MIT-licensed plugin maintained by wingoo, designed to integrate the locally logged-in Codex as a local model provider into DeepSeek Harness (DSH). This plugin eliminates the need for configuring an OpenAI API Key when using Codex within DSH while preserving DSH's native session, plugin, and tool management capabilities. After installation and restart, users can select `Codex App Server (local)` from the model selector. The plugin supports image input and writes back Codex's native image generation results. For security, the plugin enforces the App Server to use a read-only sandbox and a deny-by-default approval mode, disabling Codex