Agent Zero plugin scaffold for persistent graph workspaces.
This scaffold owns the plugin boundary for graphify: manifest metadata, default
configuration, and the package entry point that future graph workspace features
will build on.
Default config keys:
active_workspace_id: the currently selected workspace id, or an empty string when no workspace is active.workspace_store: the plugin-owned JSON file that will track workspace records.output_root: the root directory where workspace output folders will live.