fix: PrimitiveNode combo widget value not persisting in vueNodes mode (#7782)

## Summary
- Add missing v-model binding to WidgetWithControl in WidgetSelect.vue
- Trigger callback after setting widget value in PrimitiveNode to update
linked widgets

The combo widget value was lost because PrimitiveNode creates combo
widgets with controlWidget (via addValueControlWidgets), causing it to
use the WidgetWithControl branch which was missing v-model binding.

fix https://github.com/Comfy-Org/ComfyUI_frontend/issues/7694 and
https://github.com/Comfy-Org/ComfyUI_frontend/issues/7696

## Screenshots
before

https://github.com/user-attachments/assets/0a0dc668-eb71-4072-b5f7-0c20483fc1ff

after

https://github.com/user-attachments/assets/dfd2274c-8ebf-4105-821a-946063d87e9a

src/renderer/extensions/vueNodes/widgets/components/WidgetSelect.vue

@@ -12,6 +12,7 @@
   />
   <WidgetWithControl
     v-else-if="widget.controlWidget"
+    v-model="modelValue"
     :component="WidgetSelectDefault"
     :widget="widget as StringControlWidget"
   />