dsh-nous-portal-free-provider: DeepSeek Harness Plugin for the Nous Portal Free Tier

This plugin integrates the free models from Nous Portal into DeepSeek Harness (DSH). Core features include OAuth device-code login, dynamic model discovery, reasoning-level support, and an image Offload mechanism. The plugin supports single-use Refresh Tokens and provides concurrent-safe token refresh and retry strategies. Users need to install the plugin and log in via the CLI, noting the single-use nature of the token and the required DSH version.