0c5f195ee2
The deeplink-driven plugin install flow shipped in #89464 (salvage of #82735 by @serefyarar) had no docs. Adds: - user-guide/features/plugins.md: "One-click install links (Desktop)" section under Managing plugins — link forms (repo/enable/force), the confirm-first dialog contract (never auto-installs, same install-time security scanning as the CLI), hybrid-repo behavior, legacy plugin-agent/plugin-desktop routing, hermes-dev:// in dev builds, and the no-SDK anchor example. Cross-links the MCP "Add to Hermes link" equivalent. - developer-guide/desktop-plugin-sdk.md: "Distributing with an install link" section so plugin authors find the link form next to the packaging docs.