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/a11y.spec.js

@@ -0,0 +1,112 @@
+import { test, expect } from '@playwright/test'
+import AxeBuilder from '@axe-core/playwright'
+import { loginAsAdmin } from './helpers/auth.js'
+
+const publicPages = [
+  { name: 'Home', path: '/' },
+  { name: 'Join', path: '/join' },
+  { name: 'Events', path: '/events' },
+  { name: 'Coming Soon', path: '/coming-soon' },
+]
+
+const memberPages = [
+  { name: 'Member Dashboard', path: '/member/dashboard' },
+  { name: 'Member Profile', path: '/member/profile' },
+]
+
+const adminPages = [
+  { name: 'Admin Members', path: '/admin/members' },
+  { name: 'Admin Events Create', path: '/admin/events/create' },
+]
+
+test.describe('accessibility — public pages', () => {
+  for (const { name, path } of publicPages) {
+    test(`${name} has no critical a11y violations`, async ({ page }) => {
+      await page.goto(path)
+      await page.waitForLoadState('networkidle')
+
+      const results = await new AxeBuilder({ page })
+        .withTags(['wcag2a', 'wcag2aa'])
+        .analyze()
+
+      const critical = results.violations.filter(
+        (v) => v.impact === 'critical' || v.impact === 'serious'
+      )
+
+      expect(critical, `${name} has critical/serious a11y issues`).toEqual([])
+    })
+  }
+})
+
+test.describe('accessibility — member pages', () => {
+  test.beforeEach(async ({ page }) => {
+    await loginAsAdmin(page)
+  })
+
+  for (const { name, path } of memberPages) {
+    test(`${name} has no critical a11y violations`, async ({ page }) => {
+      await page.goto(path)
+      await page.waitForLoadState('networkidle')
+
+      const results = await new AxeBuilder({ page })
+        .withTags(['wcag2a', 'wcag2aa'])
+        .analyze()
+
+      const critical = results.violations.filter(
+        (v) => v.impact === 'critical' || v.impact === 'serious'
+      )
+
+      expect(critical, `${name} has critical/serious a11y issues`).toEqual([])
+    })
+  }
+})
+
+test.describe('accessibility — admin pages', () => {
+  test.beforeEach(async ({ page }) => {
+    await loginAsAdmin(page)
+  })
+
+  for (const { name, path } of adminPages) {
+    test(`${name} has no critical a11y violations`, async ({ page }) => {
+      await page.goto(path)
+      await page.waitForLoadState('networkidle')
+
+      const results = await new AxeBuilder({ page })
+        .withTags(['wcag2a', 'wcag2aa'])
+        .analyze()
+
+      const critical = results.violations.filter(
+        (v) => v.impact === 'critical' || v.impact === 'serious'
+      )
+
+      expect(critical, `${name} has critical/serious a11y issues`).toEqual([])
+    })
+  }
+})
+
+test.describe('keyboard navigation', () => {
+  test('tab through join form fields in order', async ({ page }) => {
+    await page.goto('/join')
+    await page.waitForLoadState('networkidle')
+
+    // Focus the name field and tab through
+    await page.locator('#join-name').focus()
+    expect(await page.locator('#join-name').evaluate((el) => el === document.activeElement)).toBe(true)
+
+    await page.keyboard.press('Tab')
+    // Email field should receive focus next
+    expect(await page.locator('#join-email').evaluate((el) => el === document.activeElement)).toBe(true)
+  })
+
+  test('escape closes login modal', async ({ page }) => {
+    await page.goto('/member/dashboard')
+    // Wait for login modal to appear
+    const modal = page.locator('text=Sign in to continue').or(page.locator('text=Sign in to your dashboard'))
+    await expect(modal.first()).toBeVisible({ timeout: 10000 })
+
+    await page.keyboard.press('Escape')
+
+    // Modal should close
+    await expect(modal.first()).not.toBeVisible({ timeout: 5000 })
+  })
+})