dsh-web-browse: A General-Purpose Web Browsing Plugin for DSH

`dsh-web-browse` is a general-purpose web browsing plugin for DSH, compatible with the DshDesktop shell and general-purpose browsers. It uses WebView2 extensions to address iframe limitations and provides core features such as a sidebar button, a floating search box, and a top bar for web pages. In DshDesktop, it supports search on selected text and setting synchronization, while in general-purpose browsers it mainly relies on native tab management. This plugin aims to unify the user experience and maintain cross-platform consistency.