Add Playwright e2e coverage and Node 20 pin

frontend/e2e/library.spec.ts

@@ -0,0 +1,28 @@
+import { expect, test } from '@playwright/test'
+import {
+  createAuthenticatedApiContext,
+  createTroubleshootingTree,
+  disposeApiContext,
+} from './helpers/api'
+
+test.describe('flow library smoke tests', () => {
+  test('can search for an API-created troubleshooting flow', async ({ page }) => {
+    const api = await createAuthenticatedApiContext()
+    const tree = await createTroubleshootingTree(api)
+
+    try {
+      await page.goto('/trees')
+
+      await expect(
+        page.getByRole('heading', { name: 'Flow Library' }),
+      ).toBeVisible()
+
+      await page.getByPlaceholder('Search flows...').fill(tree.name)
+      await page.getByRole('button', { name: 'Search', exact: true }).click()
+
+      await expect(page.getByText(tree.name)).toBeVisible()
+    } finally {
+      await disposeApiContext(api)
+    }
+  })
+})