Add Podman support with dynamic machine detection

[yepzdk]

Summary

• Auto-detect container runtime (podman/docker) with CONTAINER_CLI environment variable override
• Dynamically detect running podman machine instead of assuming podman-machine-default
• Add socket path detection for macOS, rootless Linux, and rootful setups
• Generate podman-specific traefik config with correct gateway IP for TCP API access

Details

Container Runtime Detection

• Podman takes precedence if both runtimes are installed
• Override with CONTAINER_CLI=docker or CONTAINER_CLI=podman

Dynamic Podman Machine Detection (macOS)

• Queries podman machine list to find the currently running machine
• Works with any machine name (e.g., podman-machine-apple-hv, custom names)
• Clear error message if no machine is running

Traefik Configuration

• Docker: Uses socket-proxy for secure Docker socket access
• Podman: Starts TCP API service in the VM, generates traefik-podman.yml with correct gateway IP

Test plan

• Test itkdev-docker-compose traefik:start with Podman on macOS
• Test itkdev-docker-compose traefik:start with Docker on macOS
• Verify traefik dashboard accessible at http://traefik.local.itkdev.dk:8080
• Test with non-default podman machine name

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