Fix promoted assets not being assets in vue (#7576)

- Fixes asset widgets which have been promoted failing to display as
asset widgets and having red names in vue mode.
- Fixes promoted subgraph widgets failing to resolve inputSpec for use
in vue mode.

| Before | After |
| ------ | ----- |
| <img width="360" alt="before"
src="https://github.com/user-attachments/assets/6c2d2763-6ac3-4769-82c5-b1ab1cc5e945"/>
| <img width="360" alt="after"
src="https://github.com/user-attachments/assets/742e218b-ec42-411a-b5a2-021820031e2a"
/>|

I'm not excited that this creates further bloat of SimplifiedWidget.

Known issue
- Similar to #7550, subgraph widgets will have an incorrect callback and
will fail to update value on a fresh reload. This can be "fixed" (made
worse) by entering and exiting the subgraph. Since this creates a
'leaked' widget callback which will then be called.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-7576-Fix-promoted-assets-not-being-assets-in-vue-2cc6d73d3650814b8734f69b225b0228)
by [Unito](https://www.unito.io)

src/stores/nodeDefStore.ts

@@ -3,6 +3,7 @@ import _ from 'es-toolkit/compat'
 import { defineStore } from 'pinia'
 import { computed, ref } from 'vue'
 
+import { isProxyWidget } from '@/core/graph/subgraph/proxyWidget'
 import type { LGraphNode } from '@/lib/litegraph/src/litegraph'
 import { transformNodeDefV1ToV2 } from '@/schemas/nodeDef/migration'
 import type {
@@ -358,10 +359,21 @@ export const useNodeDefStore = defineStore('nodeDef', () => {
     node: LGraphNode,
     widgetName: string
   ): InputSpecV2 | undefined {
-    const nodeDef = fromLGraphNode(node)
-    if (!nodeDef) return undefined
+    if (!node.isSubgraphNode()) {
+      const nodeDef = fromLGraphNode(node)
+      if (!nodeDef) return undefined
 
-    return nodeDef.inputs[widgetName]
+      return nodeDef.inputs[widgetName]
+    }
+    const widget = node.widgets?.find((w) => w.name === widgetName)
+    //TODO: resolve spec for linked
+    if (!widget || !isProxyWidget(widget)) return undefined
+
+    const { nodeId, widgetName: subWidgetName } = widget._overlay
+    const subNode = node.subgraph.getNodeById(nodeId)
+    if (!subNode) return undefined
+
+    return getInputSpecForWidget(subNode, subWidgetName)
   }
 
   /**