Support "control after generate" in vue (#6985)

Continuation of #6034 with
- Updated synchronization for seed
- Properly truncates the displayed widget value for the button
- Synchronizes control after generate state with litegraph and allows
for serialization

Several issues from original PR have not (yet) been addressed, but are
likely better moved to future PR
- fix step value being 10 (legacy system)
- ensure it works with COMBO (Fixed in #7095)
- ensure it works with FLOAT (Fixed in #7095)
- either implement or remove the config button functionality - think it
should open settings?

<img width="280" height="694" alt="image"
src="https://github.com/user-attachments/assets/f36f1cb0-237d-4bfc-bff1-e4976775cf98"
/>

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-6985-Support-control-after-generate-in-vue-2b86d73d365081d8b01ce489d887ff00)
by [Unito](https://www.unito.io)

---------

Co-authored-by: bymyself <cbyrne@comfy.org>
Co-authored-by: github-actions <github-actions@github.com>

browser_tests/fixtures/VueNodeHelpers.ts

@@ -160,7 +160,7 @@ export class VueNodeHelpers {
     return {
       input: widget.locator('input'),
       incrementButton: widget.locator('button').first(),
-      decrementButton: widget.locator('button').last()
+      decrementButton: widget.locator('button').nth(1)
     }
   }
 }

browser_tests/tests/vueNodes/widgets/int/integerWidget.spec.ts

@@ -15,7 +15,9 @@ test.describe('Vue Integer Widget', () => {
     await comfyPage.loadWorkflow('vueNodes/linked-int-widget')
     await comfyPage.vueNodes.waitForNodes()
 
-    const seedWidget = comfyPage.vueNodes.getWidgetByName('KSampler', 'seed')
+    const seedWidget = comfyPage.vueNodes
+      .getWidgetByName('KSampler', 'seed')
+      .first()
     const controls = comfyPage.vueNodes.getInputNumberControls(seedWidget)
     const initialValue = Number(await controls.input.inputValue())