dsh-theme-inkstone: Inkstone and Green Jade Color Theme

The `dsh-theme-inkstone` plugin for the DeepSeek Harness (DSH) Web client provides a mineral-inspired color scheme named “Inkstone.” It customizes the appearance by overriding 84 tokens (58 static color scales and 26 semantic tokens), without altering layout, structure, or typography, and automatically adapts to light and dark modes. Users must install the plugin and restart the `dsh web` process for the changes to take effect. Known limitations include three unresolved low-contrast color pairs and dependency scanning, making it suitable for users who want to apply a specific style while maintaining UI stability.