DeepSeek Harness Plugin: dsh-open-in-app

`dsh-open-in-app` is a DeepSeek Harness plugin designed to address the need to manually switch to a local environment after AI-generated code is produced. It provides a folder control in the session header, enabling one-click launching of a host terminal or editor to open the current workspace. Its features include an application selection menu (supporting recently used apps, whitelisted apps, and system defaults), application icon display, and path derivation. The plugin is installed via npm and requires a service restart; it includes a built-in whitelist for various terminals and editors and performs secure invocations by resolving local application paths.