feat: watch graph change (#1092)

### What problem does this PR solve?

feat: watch graph change #918 

### Type of change

- [x] New Feature (non-breaking change which adds functionality)

web/src/pages/flow/canvas/index.tsx

@@ -78,6 +78,9 @@ function FlowCanvas({ sideWidth }: IProps) {
         onKeyUp={handleKeyUp}
         onSelectionChange={onSelectionChange}
         nodeOrigin={[0.5, 0]}
+        onChange={(...params) => {
+          console.info('params:', ...params);
+        }}
         defaultEdgeOptions={{
           type: 'buttonEdge',
           markerEnd: {