dsh-reasoning-effort: Adding a Codex-style Model and Reasoning Intensity Slider to DSH

dsh-reasoning-effort is a DSH Web plugin maintained by HanaAyane, providing a Codex-style model and reasoning intensity slider below the input box. The slider levels automatically adapt based on the `reasoning.efforts` setting in the model directory and synchronize with the `/model` command. It supports light and dark themes, custom provider level guidelines, and a dismissible "big fat fish" slider button. The installation command is `dsh plugin --profile web add github:HanaAyane/dsh-reasoning-effort#main`, requiring a Web Host restart to take effect. It targets DSH 0.1.0-rc.6 and is open-sourced under the MIT license.