refactor(node-editor): move to packages/devtools for standalone use (#423)

- Move @esengine/node-editor from packages/editor/plugins to packages/devtools
- Clean up dependencies: remove unused zustand, move react to peerDependencies
- Update pnpm-workspace.yaml to include packages/devtools/*
- Package is now standalone and can be used in Cocos/Laya plugins

pnpm-workspace.yaml

@@ -7,6 +7,7 @@ packages:
   - 'packages/network-ext/*'
   - 'packages/editor/*'
   - 'packages/editor/plugins/*'
+  - 'packages/devtools/*'
   - 'packages/rust/*'
   - 'packages/tools/*'
   - 'docs'