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

packages/devtools/node-editor/module.json

@@ -0,0 +1,14 @@
+{
+  "id": "node-editor",
+  "name": "@esengine/node-editor",
+  "displayName": "Node Editor",
+  "description": "Universal node-based visual editor | 通用节点编辑器",
+  "version": "1.0.0",
+  "category": "Editor",
+  "icon": "Network",
+  "isEditorPlugin": true,
+  "isUtilityPackage": true,
+  "exports": {
+    "components": ["NodeCanvas", "NodeConnection", "NodePort"]
+  }
+}