feat: add testing infrastructure — Vitest, Playwright, CI, git hooks

Add comprehensive testing covering 420 unit/handler tests across 24 Vitest
files, 9 Playwright E2E specs, accessibility scans, and visual regression.
Includes GitHub Actions CI, Husky pre-push hook, and TESTING.md docs.

e2e/admin-events.spec.js

@@ -0,0 +1,55 @@
+import { test, expect } from './helpers/fixtures.js'
+
+test.describe('Admin events list', () => {
+  test('events list loads for admin', async ({ adminPage }) => {
+    await adminPage.goto('/admin/events')
+
+    await expect(adminPage.locator('h1')).toContainText('Events')
+  })
+
+  test('create event button present', async ({ adminPage }) => {
+    await adminPage.goto('/admin/events')
+
+    await expect(
+      adminPage.getByRole('link', { name: 'Create Event' })
+    ).toBeVisible()
+  })
+})
+
+test.describe('Admin events create', () => {
+  test('create event page loads', async ({ adminPage }) => {
+    await adminPage.goto('/admin/events/create')
+
+    await expect(adminPage.locator('h1')).toContainText('Create Event')
+  })
+
+  test('create event form has required fields', async ({ adminPage }) => {
+    await adminPage.goto('/admin/events/create')
+
+    // Title input
+    await expect(
+      adminPage.getByPlaceholder('Enter a clear, descriptive event title')
+    ).toBeVisible()
+
+    // Description textarea
+    await expect(
+      adminPage.getByPlaceholder(
+        'Provide a clear description of what attendees can expect from this event'
+      )
+    ).toBeVisible()
+
+    // Event type select (USelect renders a button with the selected value)
+    await expect(adminPage.getByText('Event Type')).toBeVisible()
+  })
+})
+
+test.describe('Admin events access control', () => {
+  test('non-admin redirect', async ({ page }) => {
+    await page.goto('/admin/events')
+
+    // Admin middleware redirects unauthenticated users to /
+    await page.waitForURL((url) => !url.pathname.startsWith('/admin'))
+
+    expect(page.url()).not.toContain('/admin/events')
+  })
+})