DSH Settings Plus: Adds a Settings Management Interface to DeepSeek Harness

`dsh-settings-plus` is an MIT-licensed plugin developed for DeepSeek Harness (DSH), designed to address the gap in settings management within plugin-based extensions. It provides form-level and file-level settings management capabilities and exposes an SDK for other plugins to register settings namespaces. The plugin is installed to a specified DSH profile via the `file:` bundle method, rather than being built as part of the host source code. Its core capabilities include enumerating registered settings namespaces and plugin composition configurations from the live `cordis` registry, defaulting to a read-only strategy to ensure security; it realizes form-level editing via `settings.section` and the schema form renderer...