dsh-ui-fortifier: DSH Web UI Enhancement Plugin

`dsh-ui-fortifier` is a client-side enhancement plugin for the DeepSeek Harness Web UI. It adopts a plugin-based architecture, providing fine-grained control by extending native UI interaction capabilities. Core features include copying session IDs, context compression, displaying Provider labels, a cascading model selector, opening the dshHome folder, and a draggable, resizable settings panel. The plugin runs as a pure Slot Surface without modifying core logic. It supports command-line installation and further development, aiming to improve users' UI customization and operational efficiency.