OpenSaozi/dsh-antigravity: Integrate Google Anti Gravity Coding Plan into DeepSeek Harness

`OpenSaozi/dsh-antigravity` is an LLM Provider plugin for DeepSeek Harness (DSH) designed to integrate models such as Gemini, Claude, and GPT-OSS from Google Anti Gravity Coding Plan or Cloud Code Assist accounts into DSH workspaces. The plugin features a lightweight design that connects directly to Cloud Code Assist via HTTPS, avoiding the need to launch additional IDE instances or background subprocesses. Core features include an independent `google-antigravity` adapter, dynamic model discovery, a built-in OAuth login page, and macOS one-click authorization.