fix progress state on Vue nodes in subgraphs (#5842)

## Summary

Fixes two errors with subgraph progress states:

1. Nodes inside subgraphs were not having progress state shown
2. Subgraph nodes (outer representation) themselves did not have a
visible progress state

1 is fixed by using locator IDs instead of local node IDs.

2 is fixed by ensuring the subgraph title button does not wrap to a
newline and thus block the progress bar under the node header.

## Changes

- **What**: Updated `useNodeExecutionState` composable to use
`nodeLocatorId` for tracking execution state across subgraph boundaries
- **What**: Modified NodeHeader layout to fix subgraph enter button
positioning with proper flexbox gap

## Review Focus

Execution state tracking accuracy for nested subgraph nodes and
NodeHeader layout consistency across different node types.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-5842-fix-progress-state-on-Vue-nodes-in-subgraphs-27c6d73d365081cb8335c8bb5dbd74f7)
by [Unito](https://www.unito.io)

---------

Co-authored-by: github-actions <github-actions@github.com>

src/renderer/extensions/vueNodes/components/NodeHeader.vue

@@ -9,7 +9,7 @@
     :data-testid="`node-header-${nodeData?.id || ''}`"
     @dblclick="handleDoubleClick"
   >
-    <div class="flex items-center justify-between relative">
+    <div class="flex items-center justify-between gap-2.5 relative">
       <!-- Collapse/Expand Button -->
       <button
         v-show="!readonly"
@@ -43,24 +43,22 @@
           data-testid="node-pin-indicator"
         />
       </div>
+      <div v-if="!readonly" class="flex items-center lod-toggle shrink-0">
+        <IconButton
+          v-if="isSubgraphNode"
+          size="sm"
+          type="transparent"
+          class="text-stone-200 dark-theme:text-slate-300"
+          data-testid="subgraph-enter-button"
+          title="Enter Subgraph"
+          @click.stop="handleEnterSubgraph"
+          @dblclick.stop
+        >
+          <i class="pi pi-external-link"></i>
+        </IconButton>
+      </div>
       <LODFallback />
     </div>
-
-    <!-- Title Buttons -->
-    <div v-if="!readonly" class="flex items-center lod-toggle">
-      <IconButton
-        v-if="isSubgraphNode"
-        size="sm"
-        type="transparent"
-        class="text-stone-200 dark-theme:text-slate-300"
-        data-testid="subgraph-enter-button"
-        title="Enter Subgraph"
-        @click.stop="handleEnterSubgraph"
-        @dblclick.stop
-      >
-        <i class="pi pi-external-link"></i>
-      </IconButton>
-    </div>
   </div>
 </template>