#7709: Using Podman in place of Docker

Running the `docker-setup.sh` on MacOS with Podman. <!-- greptile_comment --> <h2>Greptile Overview</h2> <h3>Greptile Summary</h3> This PR updates the local container setup to support Podman as an alternative runtime to Docker. `docker-setup.sh` now auto-detects `docker` vs `podman`, uses the selected runtime for `build` and `compose` commands, and exports host UID/GID into the environment. `docker-compose.yml` sets a `user:` mapping on both gateway and CLI services, aiming to avoid permission issues with bind-mounted volumes (notably on macOS/Podman). Overall, the changes fit the repo’s container-based dev/onboarding workflow by keeping the same compose topology while swapping out the underlying container CLI based on what’s installed. <h3>Confidence Score: 4/5</h3> - This PR is generally safe to merge, with some compatibility edge cases around Podman Compose detection and unconditional user mapping. - Changes are small and localized to the container setup scripts/config, but the compose detection logic likely won’t work for common `podman-compose` installs, and the global `user:` mapping may break some environments (e.g., macOS UID 501). - docker-setup.sh, docker-compose.yml <!-- greptile_other_comments_section --> _{(2/5) Greptile learns from your feedback when you react with thumbs up/down!} **Context used:** - Context from `dashboard` - CLAUDE.md ([source](https://app.greptile.com/review/custom-context?memory=fd949e91-5c3a-4ab5-90a1-cbe184fd6ce8)) - Context from `dashboard` - AGENTS.md ([source](https://app.greptile.com/review/custom-context?memory=0d0c8278-ef8e-4d6c-ab21-f5527e322f13)) <!-- /greptile_comment -->