docs(changelog): update with node architecture removal note

Added a note about the removal of node architecture in the latest release. The node architecture details are available in the v0.2.0 documentation, with plans to reintegrate it in the upcoming v2.0.0 release.

Author: jonaprieto

docs/changelog.md

@@ -19,6 +19,10 @@ specification, focusing on:
 - resource machine specifications
 - application-specific documentation
 
+The node architecture has been removed from this (latest) release, but can be
+found in the [v0.2.0](https://specs.anoma.net/v0.2.0/) release. We plan to
+integrate it back in the future, when v2.0.0 comes in.
+
 ## [v0.2.0](https://specs.anoma.net/v0.2.0/)
 
 This release introduces significant new features and improvements to the Anoma specification, including protocol adapter integration, engine simulation capabilities, and major updates to the Resource Machine specifications. Key highlights include: