feat(17-04): menu plugin admin with registry types, URL checks and tree reorder

- golem15.menu plugin, tables golem15_menu_menus and golem15_menu_menu_entries with the PHP columns plus a nullable url_pattern (D-02)
- MenuEntry BeforeSave ports PHP beforeSave: nest columns 0, menu from the parent, sort_order after the menu's last
- entry type dropdown: url, divider and the signpost registry types; reference depends on type through signpost.ReferenceOptions
- URL scheme allowlist (errors.url_scheme), target _self or _blank, menu and parent cycle checks
- menu filter, toolbar reorder/create/delete and config_reorder.yaml partitioned by menu
- navigation Menus with Menus and Menu entries, permission golem15.menu.manage_menu, en and pl phrasebooks
- TestMenuAdminSmoke

admin_permissions.go

@@ -0,0 +1,19 @@
+package menu
+
+import (
+	"git.golem15.com/golem15/sm-menu-plugin/controllers"
+	"git.golem15.com/golem15/summercms/modules/pact"
+)
+
+// Permissions is the plugin's Winter registerPermissions() catalog: the PHP
+// code golem15.menu.manage_menu on the developer and publisher roles.
+func (*Plugin) Permissions() []pact.Permission {
+	return []pact.Permission{{
+		Code:  controllers.PermissionManageMenu,
+		Tab:   "golem15.menu::lang.plugin.name",
+		Label: "golem15.menu::lang.permissions.manage_menu",
+		Roles: []string{"developer", "publisher"},
+	}}
+}
+
+var _ pact.HasPermissions = (*Plugin)(nil)