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/coming-soon.spec.js

@@ -0,0 +1,41 @@
+import { test, expect } from '@playwright/test'
+
+test.describe('coming-soon page', () => {
+  test('renders with heading and login form', async ({ page }) => {
+    await page.goto('/coming-soon')
+
+    await expect(page.locator('h1')).toContainText('Ghost Guild')
+    await expect(page.locator('input[type="email"]')).toBeVisible()
+    await expect(page.getByRole('button', { name: 'Send Magic Link' })).toBeVisible()
+  })
+
+  test('shows "Coming Soon" text for unauthenticated visitors', async ({ page }) => {
+    await page.goto('/coming-soon')
+
+    await expect(page.getByText('Coming Soon')).toBeVisible()
+  })
+})
+
+test.describe('public routes accessible when gate is off', () => {
+  test('home page loads', async ({ page }) => {
+    await page.goto('/')
+
+    // Should not redirect to /coming-soon
+    expect(page.url()).not.toContain('/coming-soon')
+    await expect(page.getByText('Ghost Guild')).toBeVisible()
+  })
+
+  test('events page loads', async ({ page }) => {
+    await page.goto('/events')
+
+    expect(page.url()).not.toContain('/coming-soon')
+    await expect(page.locator('h1')).toContainText('Events')
+  })
+
+  test('join page loads', async ({ page }) => {
+    await page.goto('/join')
+
+    expect(page.url()).not.toContain('/coming-soon')
+    await expect(page.locator('h1')).toContainText('Join Ghost Guild')
+  })
+})