dsh-oauth-newapi: New API OAuth Login and Model Routing Plugin

`dsh-oauth-newapi` is a Model Provider plugin for DeepSeek Harness (DSH), designed to manage New API instances uniformly via the OAuth protocol. It automatically discovers models, registers routes, and uses DSH’s security service to store credentials. The plugin supports account, group, and token management, addressing the issues of scattered API keys and cumbersome configuration. It is compatible with Node.js environments and is open-sourced under the MIT License.