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>

src/types/simplifiedWidget.ts

@@ -15,6 +15,28 @@ export type WidgetValue =
   | void
   | File[]
 
+const CONTROL_OPTIONS = [
+  'fixed',
+  'increment',
+  'decrement',
+  'randomize'
+] as const
+export type ControlOptions = (typeof CONTROL_OPTIONS)[number]
+
+function isControlOption(val: WidgetValue): val is ControlOptions {
+  return CONTROL_OPTIONS.includes(val as ControlOptions)
+}
+
+export function normalizeControlOption(val: WidgetValue): ControlOptions {
+  if (isControlOption(val)) return val
+  return 'randomize'
+}
+
+export type SafeControlWidget = {
+  value: ControlOptions
+  update: (value: WidgetValue) => void
+}
+
 export interface SimplifiedWidget<
   T extends WidgetValue = WidgetValue,
   O = Record<string, any>
@@ -47,4 +69,6 @@ export interface SimplifiedWidget<
 
   /** Optional input specification backing this widget */
   spec?: InputSpecV2
+
+  controlWidget?: SafeControlWidget
 }