DeepSeek Harness Plugin: Declaring Reasoning Levels for GPT, Codex, Gemini, and Other Models

This plugin is intended to resolve an issue in DeepSeek Harness (DSH) where custom gateway models cannot select a reasoning level. It uses a helper script to write reasoning capability declarations to `settings.yaml`, supports declaring six reasoning levels from `off` to `xhigh` for models such as GPT and Gemini, and supports image model markers. Installation requires manually running a PowerShell script and is limited to Windows with the desktop configuration profile; gateway restrictions on parameters should be noted during use.