test: avoid duplicate queue button e2e setup

The dropdown deliberately stays open after selecting a mode
(`@select.prevent` on DropdownMenuItem in ComfyQueueButton.vue,
introduced in #9134 as part of the Figma run-controls redesign).

The previous test asserted the menu hides after selection, which
contradicts the implementation and failed in CI. Replace it with a
behavior-meaningful assertion: selecting 'Run (On Change)' updates the
Run button label, proving the mode change took effect.

browser_tests/tests/queueButtonModes.spec.ts

@@ -0,0 +1,83 @@
+import { expect } from '@playwright/test'
+
+import type { PromptResponse } from '@/schemas/apiSchema'
+
+import { comfyPageFixture as test } from '@e2e/fixtures/ComfyPage'
+import { TestIds } from '@e2e/fixtures/selectors'
+
+test.describe('Queue button modes', { tag: '@ui' }, () => {
+  test('Run button is visible in topbar', async ({ comfyPage }) => {
+    await expect(comfyPage.runButton).toBeVisible()
+  })
+
+  test('Queue mode trigger menu is visible', async ({ comfyPage }) => {
+    const trigger = comfyPage.page.getByTestId(
+      TestIds.topbar.queueModeMenuTrigger
+    )
+    await expect(trigger).toBeVisible()
+  })
+
+  test('Clicking queue mode trigger opens mode menu', async ({ comfyPage }) => {
+    const trigger = comfyPage.page.getByTestId(
+      TestIds.topbar.queueModeMenuTrigger
+    )
+    await trigger.click()
+
+    const menu = comfyPage.page.getByRole('menu')
+    await expect(menu).toBeVisible()
+  })
+
+  test('Queue mode menu shows available modes', async ({ comfyPage }) => {
+    const trigger = comfyPage.page.getByTestId(
+      TestIds.topbar.queueModeMenuTrigger
+    )
+    await trigger.click()
+
+    const menu = comfyPage.page.getByRole('menu')
+    await expect(menu).toBeVisible()
+
+    const items = menu.getByRole('menuitem')
+    await expect(items).toHaveCount(3)
+    await expect(items.nth(0)).toHaveText('Run')
+    await expect(items.nth(1)).toHaveText('Run (On Change)')
+    await expect(items.nth(2)).toHaveText('Run (Instant)')
+  })
+
+  test('Selecting a non-default mode updates the Run button label', async ({
+    comfyPage
+  }) => {
+    const trigger = comfyPage.page.getByTestId(
+      TestIds.topbar.queueModeMenuTrigger
+    )
+    await trigger.click()
+
+    const menu = comfyPage.page.getByRole('menu')
+    await expect(menu).toBeVisible()
+
+    // Select "Run (On Change)" — a non-default mode so we observe a real change
+    const onChangeItem = menu.getByRole('menuitem').nth(1)
+    await onChangeItem.click()
+
+    await expect(comfyPage.runButton).toContainText('Run (On Change)')
+  })
+
+  test('Run button sends prompt when clicked', async ({ comfyPage }) => {
+    let promptQueued = false
+    const mockResponse: PromptResponse = {
+      prompt_id: 'test-id',
+      node_errors: {},
+      error: ''
+    }
+    await comfyPage.page.route('**/api/prompt', async (route) => {
+      promptQueued = true
+      await route.fulfill({
+        status: 200,
+        body: JSON.stringify(mockResponse)
+      })
+    })
+
+    await comfyPage.runButton.click()
+
+    await expect.poll(() => promptQueued).toBe(true)
+  })
+})