@blue-a11y/dsh-client-shortcuts: Global shortcut plugin for the dsh web GUI

`@blue-a11y/dsh-client-shortcuts` is a client-side enhancement plugin for the DeepSeek Harness web GUI, designed to improve efficiency by replacing frequent mouse operations with global keyboard shortcuts. The plugin runs in the browser; its core service, `ShortcutRegistry`, is responsible for listening to and capturing keyboard events during the capture phase and dispatching them to UI actions. It supports functions such as focusing input fields, creating or switching sessions, toggling sidebars and detail panels, adjusting themes, and scrolling through conversations. The plugin provides a settings page that allows users to record and reset key combinations, as well as automatically detect conflicts and block browser-reserved key combinations. Please note that these keybindings are only valid for the current session and revert to defaults after refreshing the page; keyboard events are passed through by default when the focus is on an input field to ensure normal input. Installation requires first configuring the DSH environment and using `ds`...