[backport cloud/1.42] fix: subgraph promoted widget input label rename (#10421)

Backport of #10195 to cloud/1.42.

Cherry-picked from the core/1.42 backport commits (identical codebase).
Test fix included: `renameWidget` test passes `parents` explicitly since
1.42 uses `parents?.length` (not `node.isSubgraphNode()` fallback). Also
includes negative test for subgraph node without parents.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10421-backport-cloud-1-42-fix-subgraph-promoted-widget-input-label-rename-32d6d73d3650813fbf60fa32a7542518)
by [Unito](https://www.unito.io)

Co-authored-by: Alexander Brown <drjkl@comfy.org>

src/composables/graph/useGraphNodeManager.ts

@@ -92,6 +92,10 @@ export interface SafeWidgetData {
    * execution ID (e.g. `"65:42"` vs the host node's `"65"`).
    */
   sourceExecutionId?: string
+  /** Tooltip text from the resolved widget. */
+  tooltip?: string
+  /** For promoted widgets, the display label from the subgraph input slot. */
+  promotedLabel?: string
 }
 
 export interface VueNodeData {
@@ -352,7 +356,8 @@ function safeWidgetMapper(
           sourceNode && app.rootGraph
             ? (getExecutionIdByNode(app.rootGraph, sourceNode) ?? undefined)
             : undefined,
-        tooltip: widget.tooltip
+        tooltip: widget.tooltip,
+        promotedLabel: isPromotedWidgetView(widget) ? widget.label : undefined
       }
     } catch (error) {
       console.warn(
@@ -803,6 +808,8 @@ export function useGraphNodeManager(graph: LGraph): GraphNodeManager {
         if (slotLabelEvent.slotType !== NodeSlotType.INPUT && nodeRef.outputs) {
           nodeRef.outputs = [...nodeRef.outputs]
         }
+        // Re-extract widget data so promotedLabel reflects the rename
+        vueNodeData.set(nodeId, extractVueNodeData(nodeRef))
       }
     }