- Add URL plugin effects (register, export_url, clear_urls) in core
- Add PluginHostnameInfo, HostnameMetadata::Plugin, and plugin registration types
- Implement plugin URL table in web UI with tableAction button and rowAction overflow menus
- Thread urlPluginMetadata (packageId, hostId, interfaceId, internalPort) as prefill to actions
- Add prefill support to PackageActionData so metadata passes through form dialogs
- Add i18n translations for plugin error messages
- Clean up plugin URLs on package uninstall