fix: allow URI drops to bubble from Vue nodes to document handler (#9463)

## Summary

Fix URI drops (e.g. dragging `<img>` thumbnails) onto Vue-rendered nodes
by letting unhandled drops bubble to the document-level `text/uri-list`
fallback in `app.ts`.

## Changes

- **What**: Removed unconditional `.stop` modifier from `@drop` in
`LGraphNode.vue`. `stopPropagation()` is now called conditionally — only
when `onDragDrop` returns `true` (file drop handled). Made `handleDrop`
synchronous since `onDragDrop` returns a plain boolean.

## Review Focus

The key insight is that `onDragDrop` (from `useNodeDragAndDrop`) returns
`false` synchronously for URI drags (no files in `DataTransfer`), so the
event must bubble to reach the document handler that fetches the URI.
The original `async` + `await` pattern would have deferred
`stopPropagation` past the synchronous propagation phase, so
`handleDrop` is now synchronous.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9463-fix-allow-URI-drops-to-bubble-from-Vue-nodes-to-document-handler-31b6d73d36508196a1b3f17e7e4837a9)
by [Unito](https://www.unito.io)

browser_tests/tests/loadWorkflowInMedia.spec.ts

@@ -67,5 +67,44 @@ test.describe(
         )
       })
     })
+
+    test('Load workflow from URL dropped onto Vue node', async ({
+      comfyPage
+    }) => {
+      const fakeUrl = 'https://example.com/workflow.png'
+      await comfyPage.page.route(fakeUrl, (route) =>
+        route.fulfill({
+          path: comfyPage.assetPath('workflowInMedia/workflow_itxt.png')
+        })
+      )
+
+      await comfyPage.settings.setSetting('Comfy.VueNodes.Enabled', true)
+      await comfyPage.vueNodes.waitForNodes()
+
+      const initialNodeCount = await comfyPage.nodeOps.getGraphNodesCount()
+
+      const node = comfyPage.vueNodes.getNodeByTitle('KSampler')
+      const box = await node.boundingBox()
+      expect(box).not.toBeNull()
+
+      const dropPosition = {
+        x: box!.x + box!.width / 2,
+        y: box!.y + box!.height / 2
+      }
+
+      await comfyPage.dragDrop.dragAndDropURL(fakeUrl, {
+        dropPosition,
+        preserveNativePropagation: true
+      })
+
+      await comfyPage.page.waitForFunction(
+        (prevCount) => window.app!.graph.nodes.length !== prevCount,
+        initialNodeCount,
+        { timeout: 10000 }
+      )
+
+      const newNodeCount = await comfyPage.nodeOps.getGraphNodesCount()
+      expect(newNodeCount).not.toBe(initialNodeCount)
+    })
   }
 )