[backport core/1.40] fix: textarea stays disabled after link disconnect on promoted widgets (#9199) (#9577)

Backport of #9199 to core/1.40.

Conflicts resolved in useGraphNodeManager.ts/test.ts — accepted incoming
promoted widget handling changes.

**Original PR:** https://github.com/Comfy-Org/ComfyUI_frontend/pull/9199
**Pipeline ticket:** 15e1f241-efaa-4fe5-88ca-4ccc7bfb3345

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9577-backport-core-1-40-fix-textarea-stays-disabled-after-link-disconnect-on-promoted-widge-31d6d73d365081619c7cfbea1bbc4463)
by [Unito](https://www.unito.io)

src/composables/graph/useGraphNodeManager.ts

@@ -68,6 +68,12 @@ export interface SafeWidgetData {
   spec?: InputSpec
   /** Input slot metadata (index and link status) */
   slotMetadata?: WidgetSlotMetadata
+  /**
+   * Original LiteGraph widget name used for slot metadata matching.
+   * For promoted widgets, `name` is `sourceWidgetName` (interior widget name)
+   * which differs from the subgraph node's input slot widget name.
+   */
+  slotName?: string
 }
 
 export interface VueNodeData {
@@ -226,9 +232,12 @@ function safeWidgetMapper(
         ...sharedEnhancements,
         callback,
         hasLayoutSize: typeof widget.computeLayoutSize === 'function',
-        isDOMWidget: isDOMWidget(widget),
-        options,
-        slotMetadata: slotInfo
+        isDOMWidget: isDOMWidget(widget) || isPromotedDOMWidget(widget),
+        options: isPromotedPseudoWidget
+          ? { ...options, canvasOnly: true }
+          : options,
+        slotMetadata: slotInfo,
+        slotName: name !== widget.name ? widget.name : undefined
       }
     } catch (error) {
       return {
@@ -341,7 +350,7 @@ export function useGraphNodeManager(graph: LGraph): GraphNodeManager {
 
     // Update only widgets with new slot metadata, keeping other widget data intact
     for (const widget of currentData.widgets ?? []) {
-      const slotInfo = slotMetadata.get(widget.name)
+      const slotInfo = slotMetadata.get(widget.slotName ?? widget.name)
       if (slotInfo) widget.slotMetadata = slotInfo
     }
   }