Add ScopeId::ROOT (#1398)

* add ScopeId::ROOT

* replace ScopeId(0) with ScopeId::ROOT

---------

Co-authored-by: Jani Mustonen <jani.mustonen@taitounited.fi>

packages/core/src/events.rs

@@ -143,7 +143,7 @@ pub struct EventHandler<'bump, T = ()> {
 impl<T> Default for EventHandler<'_, T> {
     fn default() -> Self {
         Self {
-            origin: ScopeId(0),
+            origin: ScopeId::ROOT,
             callback: Default::default(),
         }
     }