Adds marketplaceKinds to plugin/list for local, workspace-directory, and
shared-with-me; omitted params keep default local plus gated global
behavior, while explicit kinds are exact.
Exposes shareContext on plugin summaries from local share mappings and
remote workspace/shared responses, including remotePluginId and nullable
creator metadata.
Adds shared-with-me listing through /ps/plugins/workspace/shared,
renames the workspace remote namespace to workspace-directory, and keeps
direct remote read/share/install/update/delete paths gated by plugins
rather than remote_plugin.