wip: rewrite core to be template focused

packages/core/src.old/nodes/placeholder.rs

@@ -0,0 +1,8 @@
+use crate::ElementId;
+use std::cell::Cell;
+
+/// A placeholder node
+pub struct VPlaceholder {
+    pub id: Cell<Option<ElementId>>,
+    pub dynamic_index: Option<usize>,
+}