## Summary
Restores required-input validation highlighting on Vue node input slots.
## Changes
- **What**: Passes validation error state from `NodeSlots` to
`InputSlot` using node locator IDs, including subgraph and nested
subgraph execution IDs.
- **What**: Adds unit coverage for root, one-level subgraph, and nested
subgraph slot error mapping.
- **What**: Adds a Vue Nodes screenshot regression test that asserts the
missing required input slot itself receives the error highlight.
- **Dependencies**: None.
## Review Focus
- Required input errors on Vue-rendered node's slots.
- The new Playwright screenshot expectation will need the `New Browser
Test Expectation` label for Linux baseline generation.
## Screenshots (if applicable)
Before
<img width="499" height="324" alt="스크린샷 2026-05-05 오후 3 00 44"
src="https://github.com/user-attachments/assets/285fdf91-6d7e-480b-99b9-715705f78914"
/>
After
<img width="482" height="356" alt="스크린샷 2026-05-05 오후 3 01 11"
src="https://github.com/user-attachments/assets/51b8db49-eb9c-4155-8aa5-109c0bd7699b"
/>
┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-11950-fix-highlight-missing-input-slots-on-Vue-nodes-3576d73d365081bd85bfd1ea149d45c5)
by [Unito](https://www.unito.io)
---------
Co-authored-by: github-actions <github-actions@github.com>
0307281ff2