Scaffolds comprehensive testing setup for Next.js applications including Vitest unit tests, React Testing Library component tests, and Playwright E2E flows with accessibility testing via axe-core. This skill should be used when setting up test infrastructure, generating test files, creating test utilities, adding accessibility checks, or configuring testing frameworks for Next.js projects. Trigger terms include setup testing, scaffold tests, vitest, RTL, playwright, e2e tests, component tests, u