[Cursor] Update README to introduce cookiecutter template

[grapeot]

[Cursor] Update README to introduce cookiecutter template

This PR updates the main README to introduce the new cookiecutter template feature. Key changes include:

1. Added cookiecutter installation and usage instructions as the recommended setup method
2. Updated the environment setup section to be more concise and accurate
3. Added a note about automatic Playwright installation for screenshot verification features

These changes make it easier for users to get started with the project by:

• Providing a more automated setup process through cookiecutter
• Clarifying that Playwright browsers are installed on-demand
• Streamlining the environment setup instructions

The cookiecutter template (in the template branch) provides a standardized project structure and automated setup, making it easier for users to get started with the advanced AI capabilities.