baisbt/dsh-plugin-webrelay: DSH Web Relay Plugin

`dsh-plugin-webrelay` is a DSH plugin that embeds external AI web pages into the right-hand panel via a built-in reverse proxy. It features a "Lightning Button" to streamline prompt optimization and collaborative refinement workflows, and supports site management, capture archiving, and agent tool integration. With zero hard dependencies and a "read-only by default" security mechanism, it eliminates the friction of switching between DSH and external AI services.