fix(native-dom): clear node_id_mapping when nodes are removed

When `remove_node` or `replace_node_with` removes a node from the DOM,
the corresponding entry in `node_id_mapping` was not being cleared.
This left stale ElementId → NodeId mappings.

Since dioxus-core recycles ElementIds aggressively, a recycled ElementId
could find a stale mapping in `assign_node_id`, which would then call
`remove_node_if_unparented` on either:
- An already-removed node (causing panic in blitz-dom: "invalid key")
- A node still on the mutation stack waiting to be attached (corrupting
  the DOM by removing nodes that should be inserted)

This fix clears the mapping immediately when nodes are removed, ensuring
the invariant: if `node_id_mapping[eid] = Some(nid)`, then `nid` is valid
in blitz-dom.

Author: nikhiljha

packages/native-dom/src/mutation_writer.rs

@@ -144,6 +144,9 @@ impl WriteMutations for MutationWriter<'_> {
     fn replace_node_with(&mut self, id: ElementId, m: usize) {
         trace!("replace_node_with id:{} m:{}", id.0, m);
         let (anchor_node_id, new_node_ids) = self.state.anchor_and_nodes(id, m);
+        if let Some(mapping) = self.state.node_id_mapping.get_mut(id.0) {
+            *mapping = None;
+        }
         self.docm.replace_node_with(anchor_node_id, &new_node_ids);
     }
 
@@ -160,6 +163,9 @@ impl WriteMutations for MutationWriter<'_> {
     fn remove_node(&mut self, id: ElementId) {
         trace!("remove_node id:{}", id.0);
         let node_id = self.state.element_to_node_id(id);
+        if let Some(mapping) = self.state.node_id_mapping.get_mut(id.0) {
+            *mapping = None;
+        }
         self.docm.remove_node(node_id);
     }