fix: prevent infinite node resize loop in Vue mode (#9177)

## Summary

Fix infinite node resize loop in Vue mode where textarea widgets caused
nodes to grow ~33px per frame indefinitely.

## Changes

- **What**: Two feedback loops broken in the LiteGraph↔Vue layout sync:
1. `_arrangeWidgets()` in LiteGraph's draw loop was calling `setSize()`
every frame with its own computed widget height, which disagreed with
Vue's DOM-measured height. Guarded with `!LiteGraph.vueNodesMode`.
2. `useLayoutSync` was calling `setSize()` which triggers the size
setter → writes back to layoutStore with `source=Canvas` →
`handleLayoutChange` updates CSS vars → ResizeObserver fires → loop.
Changed to direct array assignment (matching the existing position sync
pattern).

## Review Focus

- The `_arrangeWidgets` guard: in Vue mode, the DOM/ResizeObserver is
the source of truth for node sizing, so LiteGraph should not grow nodes
via `setSize()`. Verify no Vue-mode features depend on this growth path.
- The `useLayoutSync` change: `liteNode.size[0] = ...` modifies `_size`
via the getter without triggering the setter, avoiding the Canvas-source
bounce. `onResize` is still called. Verify no downstream code relies on
the setter side effects when syncing from layout store.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-9177-fix-prevent-infinite-node-resize-loop-in-Vue-mode-3116d73d365081e4ad88f1cfad51df18)
by [Unito](https://www.unito.io)

Co-authored-by: Amp <amp@ampcode.com>

src/renderer/core/layout/sync/useLayoutSync.ts

@@ -50,8 +50,12 @@ export function useLayoutSync() {
           liteNode.size[0] !== layout.size.width ||
           liteNode.size[1] !== layout.size.height
         ) {
-          // Use setSize() to trigger onResize callback
-          liteNode.setSize([layout.size.width, layout.size.height])
+          // Update internal size directly (like position above) to avoid
+          // the size setter writing back to layoutStore with Canvas source,
+          // which would create a feedback loop through handleLayoutChange.
+          liteNode.size[0] = layout.size.width
+          liteNode.size[1] = layout.size.height
+          liteNode.onResize?.(liteNode.size)
         }
       }