Add macOS VM support using cua-computer and lume virtualization

[f-trycua]

This PR adds a new CuaMacOSComputer implementation that leverages the cua-computer package and lume virtualization to enable the CUA agent to operate within a macOS virtual machine.

Changes:

• Add CuaMacOSComputer implementation in computers/cua.py
• Add CLI support for the "cua-macos" computer option
• Create examples/macos_finder_example.py demonstrating Finder and TextEdit interactions
• Update README with setup instructions and macOS VM documentation

Requirements:

• cua-computer package
• lume CLI for VM management
• macOS VM image (macos-sequoia-cua:latest)

This implementation allows CUA to interact with a full macOS desktop environment beyond just browser interactions, enabling automation of native macOS applications.

[ibigio]

tl;dr please adhere to new computer structure and contributing process

Hi! Thanks for your contribution – we'd love to get it reviewed and merged. To better support custom CUA computers we've created a contrib directory to co-locate community contributions and automatically run basic smoke tests.

Please make sure you complete the three main steps:

1. Move computers/contrib and update configs
2. Pass tests & do manual testing
3. Submit PR with required information

These are explained in detail in the contributing section of the README.

Thanks again!

[f-trycua]

@ibigio @katia-openai - this should be good to go, please let us know.

[f-trycua]

@ibigio @katia-openai any updates on this PR? We've adhered to the new computer structure and contributing process