feat: add getNodesByTitle and getNodeByTitleNth helpers to VueNodeHelpers (#10666)

## Summary

Add helpers for safely interacting with nodes that share the same title
without hitting Playwright strict mode.

## Changes

- **What**: Added `getNodesByTitle(title)` and `getNodeByTitleNth(title,
index)` to `VueNodeHelpers`. Updated `docs/guidance/playwright.md` with
a gotcha note about duplicate node names.

## Review Focus

These are purely additive helpers — no existing behavior changes.
`getNodesByTitle` returns all matching nodes (callers use `.nth()` to
pick), and `getNodeByTitleNth` is a convenience wrapper. The existing
`selectNodes(nodeIds)` by-ID method is unchanged.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10666-feat-add-getNodesByTitle-and-getNodeByTitleNth-helpers-to-VueNodeHelpers-3316d73d3650812eabe6e56a768a34d2)
by [Unito](https://www.unito.io)

browser_tests/fixtures/VueNodeHelpers.ts

@@ -31,10 +31,14 @@ export class VueNodeHelpers {
   }
 
   /**
-   * Get locator for a Vue node by the node's title (displayed name in the header)
+   * Get locator for Vue nodes by the node's title (displayed name in the header).
+   * Matches against the actual title element, not the full node body.
+   * Use `.first()` for unique titles, `.nth(n)` for duplicates.
    */
   getNodeByTitle(title: string): Locator {
-    return this.page.locator(`[data-node-id]`).filter({ hasText: title })
+    return this.page.locator('[data-node-id]').filter({
+      has: this.page.locator('[data-testid="node-title"]', { hasText: title })
+    })
   }
 
   /**

docs/guidance/playwright.md

@@ -110,6 +110,7 @@ Tags are respected by config:
 
 - Check `browser_tests/assets/` for test data and fixtures
 - Use realistic ComfyUI workflows for E2E tests
+- When multiple nodes share the same title (e.g. two "CLIP Text Encode" nodes), use `vueNodes.getNodeByTitle(name).nth(n)` to pick a specific one. Never interact with the bare locator when titles are non-unique — Playwright strict mode will fail.
 
 ## Running Tests