* feat(shared): scope plugin action descriptors
* feat(plugin-sdk): instance-scoped settings actions
* feat(plugins): run instance-scoped actions from the admin settings dialog
* feat(admin): instance-scoped plugin actions in the settings dialog
* fix(plugins): surface instance actions without instance fields and harden the action gate
* docs(plugin-sdk): note that hosts before 4.2.0 ignore action scope
* fix(admin): open the dialog for instance actions, explain inactive 404s, guard the save window
* docs(wiki): plugin pages for instance actions and the admin panel changes
jubnl