How to fix net::ERR_CONNECTION_REFUSED in Playwright navigation?

net::ERR_CONNECTION_REFUSED means nothing is listening on the target host/port.

Start the web server before tests and verify baseURL or target URL.

// playwright.config.ts
export default {
  use: { baseURL: 'http://127.0.0.1:3000' },
  webServer: {
    command: 'npm run dev',
    url: 'http://127.0.0.1:3000',
    reuseExistingServer: true,
  },
};

This removes race conditions where tests run before the app is ready.