feat: add WidgetValueStore for centralized widget value management (#8594)

## Summary

Implements Phase 1 of the **Vue-owns-truth** pattern for widget values.
Widget values are now canonical in a Pinia store; `widget.value`
delegates to the store while preserving full backward compatibility.

## Changes

- **New store**: `src/stores/widgetValueStore.ts` - centralized widget
value storage with `get/set/remove/removeNode` API
- **BaseWidget integration**: `widget.value` getter/setter now delegates
to store when widget is associated with a node
- **LGraphNode wiring**: `addCustomWidget()` automatically calls
`widget.setNodeId(this.id)` to wire widgets to their nodes
- **Test fixes**: Added Pinia setup to test files that use widgets

## Why

This foundation enables:
- Vue components to reactively bind to widget values via `computed(() =>
store.get(...))`
- Future Yjs/CRDT backing for real-time collaboration
- Cleaner separation between Vue state and LiteGraph rendering

## Backward Compatibility

| Extension Pattern | Status |
|-------------------|--------|
| `widget.value = x` | ✅ Works unchanged |
| `node.widgets[i].value` | ✅ Works unchanged |
| `widget.callback` | ✅ Still fires |
| `node.onWidgetChanged` | ✅ Still fires |

## Testing

- ✅ 4252 unit tests pass
- ✅ Build succeeds

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-8594-feat-add-WidgetValueStore-for-centralized-widget-value-management-2fc6d73d36508160886fcb9f3ebd941e)
by [Unito](https://www.unito.io)

---------

Co-authored-by: Amp <amp@ampcode.com>
Co-authored-by: github-actions <github-actions@github.com>
Co-authored-by: GitHub Action <action@github.com>

src/platform/settings/composables/useLitegraphSettings.ts

@@ -2,7 +2,6 @@ import { watchEffect } from 'vue'
 
 import {
   CanvasPointer,
-  LGraph,
   LGraphNode,
   LiteGraph
 } from '@/lib/litegraph/src/litegraph'
@@ -163,10 +162,4 @@ export const useLitegraphSettings = () => {
       'Comfy.EnableWorkflowViewRestore'
     )
   })
-
-  watchEffect(() => {
-    LGraph.deduplicateSubgraphIds = settingStore.get(
-      'Comfy.Graph.DeduplicateSubgraphNodeIds'
-    )
-  })
 }

src/platform/settings/constants/coreSettings.ts

@@ -1211,7 +1211,8 @@ export const CORE_SETTINGS: SettingParams[] = [
     tooltip:
       'Automatically reassign duplicate node IDs in subgraphs when loading a workflow.',
     type: 'boolean',
-    defaultValue: false,
+    deprecated: true,
+    defaultValue: true,
     experimental: true,
     versionAdded: '1.40.0'
   }