Google Antigravity (agy CLI) models for DeepSeek Harness — streaming chat, thinking, tool activity, usage, in-GUI Google OAuth login

Google Antigravity (agy) OAuth auth + model access plugin for DeepSeek Harness: multi-account pool, 429 rotation, device fingerprinting, CLI and web login.

DSH 模型管理层：网关可达性探测、模型目录拉取、DeepSeek + MiniMax/智谱/Moonshot/StepFun 余额与配额、本月用量统计、余额预警、Provider 健康看板，再把本机装好的 codex / claude / agy 注册成子代理（装了才出现）。零运行时依赖，不改动 DSH 安装。