Implement Phase 8: Testing & Deployment

Testing Infrastructure:
- Configure Jest with Next.js integration and TypeScript support
- Add React Testing Library with proper setup for Next.js components
- Install and configure Playwright for E2E testing
- Create jest.setup.ts with mocks for Next.js router and browser APIs
- Add CSS module mocking with identity-obj-proxy

Unit Tests:
- Create LoadingFallback component tests covering all 5 variants
- Create tracking API tests for data transformation logic
- Test createActivity, getActivities data structure conversions
- Verify frontend (timestamp/data) to backend (startedAt/metadata) mapping

E2E Tests (Playwright):
- Create comprehensive tracking flow tests
- Test navigation to all tracker pages (feeding, sleep, diaper)
- Test homepage Today's Summary display
- Test AI Assistant and Analytics navigation
- Test feeding, sleep, and diaper tracker UI elements
- Configure multi-browser testing (Chrome, Firefox, Safari, Mobile)

CI/CD Pipeline (GitHub Actions):
- Create automated CI/CD workflow for master/main branches
- Run linting on every push and PR
- Execute unit tests with coverage reporting
- Run E2E tests (Chromium) in CI environment
- Build application and upload artifacts
- Upload test coverage to Codecov
- Upload Playwright test reports as artifacts

Test Scripts:
- npm test: Run Jest unit tests
- npm run test⌚ Run tests in watch mode
- npm run test:coverage: Generate coverage report
- npm run test:e2e: Run Playwright E2E tests
- npm run test:e2e:ui: Run E2E tests with UI mode
- npm run test:e2e:headed: Run E2E tests in headed mode

Documentation:
- Create comprehensive testing guide (tests/README.md)
- Document test structure and best practices
- Add troubleshooting section for common issues
- Include useful commands for debugging tests

Coverage Thresholds:
- Branches: 70%
- Functions: 70%
- Lines: 70%
- Statements: 70%

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

maternal-web/playwright.config.ts

@@ -0,0 +1,46 @@
+import { defineConfig, devices } from '@playwright/test';
+
+export default defineConfig({
+  testDir: './tests/e2e',
+  fullyParallel: true,
+  forbidOnly: !!process.env.CI,
+  retries: process.env.CI ? 2 : 0,
+  workers: process.env.CI ? 1 : undefined,
+  reporter: 'html',
+  use: {
+    baseURL: 'http://localhost:3030',
+    trace: 'on-first-retry',
+    screenshot: 'only-on-failure',
+  },
+
+  projects: [
+    {
+      name: 'chromium',
+      use: { ...devices['Desktop Chrome'] },
+    },
+    {
+      name: 'firefox',
+      use: { ...devices['Desktop Firefox'] },
+    },
+    {
+      name: 'webkit',
+      use: { ...devices['Desktop Safari'] },
+    },
+    // Mobile viewports
+    {
+      name: 'Mobile Chrome',
+      use: { ...devices['Pixel 5'] },
+    },
+    {
+      name: 'Mobile Safari',
+      use: { ...devices['iPhone 12'] },
+    },
+  ],
+
+  webServer: {
+    command: 'npm run dev',
+    url: 'http://localhost:3030',
+    reuseExistingServer: !process.env.CI,
+    timeout: 120000,
+  },
+});