Add new numberControlWidget.spec.ts with tests covering GraphCanvas.vue
lines 355-366 (0% coverage). Tests verify control widget labels update
when toggling between 'before' and 'after' modes, including multi-node
traversal, widgetless node handling, canvas dirty marking, linkedWidgets
label updates, and subgraph node traversal.
- Add DevToolsNodeWithComboControlWidget for combo+filter list testing
- Move Number widget tests from widget.spec.ts to new file
- Add subgraph WidgetControlMode test to subgraphPromotion.spec.ts