Add Playwright e2e coverage and Node 20 pin

frontend/e2e/helpers/auth.ts

@@ -0,0 +1,17 @@
+import { expect, type Page } from '@playwright/test'
+
+const TEST_USER_EMAIL =
+  process.env.PLAYWRIGHT_TEST_EMAIL || 'teamadmin@resolutionflow.example.com'
+const TEST_USER_PASSWORD =
+  process.env.PLAYWRIGHT_TEST_PASSWORD || 'TestPass123!'
+
+export async function signIn(page: Page) {
+  await page.goto('/login')
+
+  await expect(page.getByTestId('login-form')).toBeVisible()
+  await page.getByLabel('Email address').fill(TEST_USER_EMAIL)
+  await page.getByLabel('Password').fill(TEST_USER_PASSWORD)
+  await page.getByTestId('login-submit').click()
+
+  await expect(page.getByTestId('app-shell')).toBeVisible()
+}