test: FE-233 add failing spec for multi_select combo widgets in Nodes 2.0

Reproduces the #bug-dump report from Kosinkadink using ComfyUI_devtools'
`DevToolsMultiSelectNode`: Vue Nodes routes ComponentWidget instances
(type=custom, no DOM element) through WidgetLegacy, which renders a blank
canvas instead of the PrimeVue MultiSelect component. The new e2e asserts
an interactive multi-select trigger and that picking two options yields an
array value. The test is expected to fail on main until the fix lands.

Fixes FE-233
Source: Slack https://comfy-organization.slack.com/archives/C0A4XMHANP3/p1776737678080949

browser_tests/tests/vueNodes/widgets/combo/multiSelectComboWidget.spec.ts

@@ -0,0 +1,97 @@
+import type { ComfyWorkflowJSON } from '@/platform/workflow/validation/schemas/workflowSchema'
+
+import {
+  comfyExpect as expect,
+  comfyPageFixture as test
+} from '@e2e/fixtures/ComfyPage'
+import type { TestGraphAccess } from '@e2e/types/globals'
+
+// Repro lifted from #bug-dump (Jedrzej Kosinski, 2026-04-21): `multi_select`
+// combo widgets declared with `ComfyUI_devtools`'s `DevToolsMultiSelectNode`
+// never render as a multi-select control in Nodes 2.0. Vue Nodes routes
+// ComponentWidget instances (widget.type === 'custom', no DOM element) to
+// `WidgetLegacy`, which expects a canvas `draw` callback the component widget
+// does not provide — so the node renders a blank canvas widget instead of
+// PrimeVue's MultiSelect.
+const multiSelectWorkflow: ComfyWorkflowJSON = {
+  id: 'fe-233-multi-select-regression',
+  revision: 0,
+  last_node_id: 1,
+  last_link_id: 0,
+  nodes: [
+    {
+      id: 1,
+      type: 'DevToolsMultiSelectNode',
+      pos: [200, 200],
+      size: [360, 140],
+      flags: {},
+      order: 0,
+      mode: 0,
+      inputs: [],
+      outputs: [
+        {
+          name: 'STRING',
+          type: 'STRING',
+          links: null
+        }
+      ],
+      properties: { 'Node name for S&R': 'DevToolsMultiSelectNode' },
+      widgets_values: [[]]
+    }
+  ],
+  links: [],
+  groups: [],
+  config: {},
+  extra: {},
+  version: 0.4
+}
+
+test.describe(
+  'FE-233 multi_select combo regression',
+  { tag: ['@vue-nodes', '@regression'] },
+  () => {
+    test.beforeEach(async ({ comfyPage }) => {
+      await comfyPage.workflow.loadGraphData(multiSelectWorkflow)
+      await comfyPage.vueNodes.waitForNodes(1)
+    })
+
+    test('renders an interactive multi-select widget and accepts multiple values', async ({
+      comfyPage
+    }) => {
+      const node = comfyPage.vueNodes.getNodeByTitle('Multi Select Node')
+
+      // The multi_select widget must surface as an interactive control with
+      // an ARIA role. In the broken state Vue Nodes renders this as a legacy
+      // canvas widget (no role, no accessible options), so the listbox-style
+      // trigger never appears.
+      const trigger = node
+        .getByRole('combobox', { name: 'foo', exact: true })
+        .or(node.getByRole('listbox', { name: 'foo', exact: true }))
+      await expect(trigger.first()).toBeVisible({ timeout: 3000 })
+      await trigger.first().click()
+
+      await comfyPage.page
+        .getByRole('option', { name: 'A', exact: true })
+        .click()
+      await comfyPage.page
+        .getByRole('option', { name: 'B', exact: true })
+        .click()
+      await comfyPage.page.keyboard.press('Escape')
+
+      // Underlying widget value must be an array holding both selections.
+      // In the broken state the value is either untouched (empty array / no
+      // widget) or collapses to a single string under single-select semantics.
+      const widgetValue = await comfyPage.page.evaluate(() => {
+        const graph = window.graph as unknown as TestGraphAccess | undefined
+        if (!graph) return null
+        const multiSelectNode = Object.values(graph._nodes_by_id).find(
+          (n) => n.type === 'DevToolsMultiSelectNode'
+        )
+        return multiSelectNode?.widgets?.[0]?.value ?? null
+      })
+
+      expect(Array.isArray(widgetValue)).toBe(true)
+      expect(widgetValue).toEqual(expect.arrayContaining(['A', 'B']))
+    })
+  }
+)