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

controllers/menus.go

@@ -0,0 +1,31 @@
+package controllers
+
+import (
+	"git.golem15.com/golem15/sm-menu-plugin/models"
+	"git.golem15.com/golem15/summercms/modules/pact"
+)
+
+// MenusControllerID is the cabana controller id of the Menus screen.
+const MenusControllerID = "golem15.menu.menus"
+
+// menusAdminController lists and edits menus: name, code, CSS class and the
+// active switch.
+type menusAdminController struct{}
+
+func (menusAdminController) ID() string { return MenusControllerID }
+
+func (menusAdminController) ModelName() string { return `Golem15\Menu\Models\Menu` }
+
+func (menusAdminController) ConfigDir() string { return "controllers/menus" }
+
+func (menusAdminController) RequiredPermissions() []string {
+	return []string{PermissionManageMenu}
+}
+
+func (menusAdminController) NewRecord() any { return &models.Menu{} }
+
+var (
+	_ pact.AdminController   = menusAdminController{}
+	_ pact.AdminPermissioned = menusAdminController{}
+	_ pact.AdminRecordSource = menusAdminController{}
+)