feat: implement URL plugins with table/row actions and prefill support

- 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

core/locales/i18n.yaml

@@ -1243,6 +1243,21 @@ backup.target.cifs.target-not-found-id:
   fr_FR: "ID de cible de sauvegarde %{id} non trouvé"
   pl_PL: "Nie znaleziono ID celu kopii zapasowej %{id}"
 
+# service/effects/net/plugin.rs
+net.plugin.manifest-missing-plugin:
+  en_US: "manifest does not declare the \"%{plugin}\" plugin"
+  de_DE: "Manifest deklariert das Plugin \"%{plugin}\" nicht"
+  es_ES: "el manifiesto no declara el plugin \"%{plugin}\""
+  fr_FR: "le manifeste ne déclare pas le plugin \"%{plugin}\""
+  pl_PL: "manifest nie deklaruje wtyczki \"%{plugin}\""
+
+net.plugin.binding-not-found:
+  en_US: "binding not found: %{binding}"
+  de_DE: "Bindung nicht gefunden: %{binding}"
+  es_ES: "enlace no encontrado: %{binding}"
+  fr_FR: "liaison introuvable : %{binding}"
+  pl_PL: "powiązanie nie znalezione: %{binding}"
+
 # net/ssl.rs
 net.ssl.unreachable:
   en_US: "unreachable"