Explore act for local GHA testing on macOS with Podman

[AriESQ]

Summary

Evaluate and implement act for running GitHub Actions workflows locally on macOS using Podman as the container backend.

Motivation

• Faster feedback loop when editing .github/workflows/ files — no need to commit/push to test changes
• Ability to run workflows (e.g. scrape-stars, scrape-readmes) locally on demand

Setup Notes

• act is available via brew install act
• On macOS, Podman runs containers inside a Linux VM (podman machine); the socket is tunneled to the host
• act needs DOCKER_HOST pointed at the Podman socket: unix://~/.local/share/containers/podman/machine/podman.sock
• Start the VM first: podman machine start

Tasks

• Install act via Homebrew
• Confirm Podman machine socket works as Docker API endpoint for act
• Run a simple workflow in dry-run mode (act -n) to validate setup
• Run scrape-stars or scrape-readmes locally end-to-end
• Document the local dev setup (secrets handling, GITHUB_TOKEN, etc.)