test: Add E2E test framework with Playwright

feat: Basic Homepage elements

tests/e2e/auth.spec.ts

@@ -0,0 +1,46 @@
+import { test, expect } from '@playwright/test'
+import { deleteAllMail, getMagicLink } from './helpers/mailpit'
+
+const TEST_EMAIL = 'e2e-test@example.com'
+
+test.beforeEach(async () => {
+  await deleteAllMail()
+})
+
+test.describe('Auth flow', () => {
+  test('splash → login → magic link → home', async ({ page }) => {
+    // Splash page shows logo and login button
+    await page.goto('/')
+    await expect(page.getByRole('img', { name: 'OYS Borrow a Boat' })).toBeVisible()
+    await expect(page.getByRole('link', { name: 'Log In' })).toBeVisible()
+
+    // Navigate to login page
+    await page.getByRole('link', { name: 'Log In' }).click()
+    await expect(page).toHaveURL('/login')
+    await expect(page.getByText('Sign In')).toBeVisible()
+
+    // Submit email for magic link
+    await page.getByPlaceholder('you@example.com').fill(TEST_EMAIL)
+    await page.getByRole('button', { name: 'Send Sign-In Link' }).click()
+    await expect(page.getByText('Check your email')).toBeVisible()
+
+    // Fetch magic link from Mailpit, then follow the Supabase verify redirect
+    // server-side (Node.js fetch) to get our app's callback URL.
+    // Playwright's headless shell can't reach 127.0.0.1:54321 directly.
+    const magicLink = await getMagicLink(TEST_EMAIL)
+    const redirectRes = await fetch(magicLink, { redirect: 'manual' })
+    const callbackUrl = redirectRes.headers.get('location')
+    if (!callbackUrl) throw new Error('Supabase did not redirect to app callback')
+    await page.goto(callbackUrl)
+
+    // Auth callback redirects to home (authenticated state)
+    await expect(page).toHaveURL('/')
+    await expect(page.getByText('Welcome to OYS Borrow a Boat')).toBeVisible()
+  })
+
+  test('unauthenticated access to protected route redirects to splash', async ({ page }) => {
+    await page.goto('/dashboard')
+    await expect(page).toHaveURL('/')
+    await expect(page.getByRole('link', { name: 'Log In' })).toBeVisible()
+  })
+})