feat: add assertHasItems and openFor to ContextMenu page object (#10659)

## Summary

Add composite assertion and scoped opening methods to the `ContextMenu`
Playwright page object.

## Changes

- **What**: Added `assertHasItems(items: string[])` using
`expect.soft()` per item, and `openFor(locator: Locator)` which
right-clicks and waits for menu visibility. Fully backward-compatible.

## Review Focus

Both methods reuse existing locators (`primeVueMenu`, `litegraphMenu`,
`getByRole("menuitem")`). `openFor` uses `.or()` to handle both menu
types.

┆Issue is synchronized with this [Notion
page](https://www.notion.so/PR-10659-feat-add-assertHasItems-and-openFor-to-ContextMenu-page-object-3316d73d36508193af45da7d3af4f50c)
by [Unito](https://www.unito.io)

browser_tests/fixtures/components/ContextMenu.ts

@@ -1,3 +1,4 @@
+import { expect } from '@playwright/test'
 import type { Locator, Page } from '@playwright/test'
 
 export class ContextMenu {
@@ -33,6 +34,20 @@ export class ContextMenu {
     return primeVueVisible || litegraphVisible
   }
 
+  async assertHasItems(items: string[]): Promise<void> {
+    for (const item of items) {
+      await expect
+        .soft(this.page.getByRole('menuitem', { name: item }))
+        .toBeVisible()
+    }
+  }
+
+  async openFor(locator: Locator): Promise<this> {
+    await locator.click({ button: 'right' })
+    await expect.poll(() => this.isVisible()).toBe(true)
+    return this
+  }
+
   async waitForHidden(): Promise<void> {
     const waitIfExists = async (locator: Locator, menuName: string) => {
       const count = await locator.count()