Add UI code for configuring subgraphNode widgets (#5826)

The third PR for managing display of widgets on subgraph nodes. This is
the one that actually makes the functionality usable and user visible.

Adds
- A right-side modal for configuring which widgets are promoted,
accessed by right click or selection toolbar
- This menu allows for re-arranging widget order by dragging and
dropping.
- Indicators inside the subgraph for which widgets have been promoted.
- Context menu options for promoting or demoting widget inside of a
subgraph.
<img width="767" height="694" alt="image"
src="https://github.com/user-attachments/assets/4f78645d-7b26-48ba-8c49-78f4807e89e8"
/>
<img width="784" height="435" alt="image"
src="https://github.com/user-attachments/assets/7005c730-a732-481e-befb-57019a8a31a7"
/>


Known issues
- Some preview widgets are not added to a node until a draw operation
occurs. The code does not yet have a way of determining which nodes
should have draw operations forced to facilitate initial widget
creation.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5826-Add-UI-code-for-configuring-subgraphNode-widgets-27c6d73d36508146accbf395e5bcd36a)
by [Unito](https://www.unito.io)

src/lib/litegraph/src/LGraphCanvas.ts

@@ -1862,13 +1862,13 @@ export class LGraphCanvas
     this.#dirty()
   }
 
-  openSubgraph(subgraph: Subgraph): void {
+  openSubgraph(subgraph: Subgraph, fromNode: SubgraphNode): void {
     const { graph } = this
     if (!graph) throw new NullGraphError()
 
     const options = {
       bubbles: true,
-      detail: { subgraph, closingGraph: graph },
+      detail: { subgraph, closingGraph: graph, fromNode },
       cancelable: true
     }
     const mayContinue = this.canvas.dispatchEvent(
@@ -2794,7 +2794,7 @@ export class LGraphCanvas
         if (pos[1] < 0 && !inCollapse) {
           node.onNodeTitleDblClick?.(e, pos, this)
         } else if (node instanceof SubgraphNode) {
-          this.openSubgraph(node.subgraph)
+          this.openSubgraph(node.subgraph, node)
         }
 
         node.onDblClick?.(e, pos, this)
@@ -8007,7 +8007,7 @@ export class LGraphCanvas
       if (Object.keys(this.selected_nodes).length > 1) {
         options.push(
           {
-            content: 'Convert to Subgraph 🆕',
+            content: 'Convert to Subgraph',
             callback: () => {
               if (!this.selectedItems.size)
                 throw new Error('Convert to Subgraph: Nothing selected.')
@@ -8042,7 +8042,7 @@ export class LGraphCanvas
     } else {
       options = [
         {
-          content: 'Convert to Subgraph 🆕',
+          content: 'Convert to Subgraph',
           callback: () => {
             // find groupnodes, degroup and select children
             if (this.selectedItems.size) {