dsh-eyecare: Add Eye Care Mode Switch for DSH Web

dsh-eyecare is a DeepSeek Harness (DSH) Web plugin maintained by Yummyxl, released under the MIT License. It aims to resolve the issue of standard DSH themes being too bright or too cool by providing a low-stimulation "bean paste green" eye-protection color scheme, thereby optimizing the visual experience for long-term reading and debugging. Core features include an eye-care mode toggle in "Settings - General - Appearance," support for light, dark, and system theme following modes, automatic state persistence, and the preservation of hierarchy such as code blocks. Users can customize the color scheme by modifying `EYE_CARE_TOKENS`. Installation requires ensuring `pnpm` is installed, followed by executing `dsh plugin --profile web add dsh-eyecare` or cloning the repository and running `insta...`