Add container-compose: docker-compose compatibility layer

[demostenex]

Type of Change

• New feature
• Documentation update

Motivation and Context

Users migrating from Docker commonly describe their applications in docker-compose.yml files. The container CLI operates on individual containers and has no equivalent of docker compose up. This PR fills that gap with a lightweight Python script (container-compose) that reads a standard compose file and translates each subcommand into the equivalent container invocations.

No changes are made to the container binary or any Swift sources — this is entirely additive, living in examples/ and docs/.

What's included

examples/compose-example/container-compose — the script itself (~800 lines of Python 3, single dependency: PyYAML). Supported subcommands: up, down, ps, logs, exec, build, pull, start, stop, restart, rm, run, config.

Key behaviours:

• Services start in depends_on topological order (list and condition-dict form)
• Networks and named volumes are created automatically and prefixed with the project name
• Every container is labelled with com.container-compose.project and com.container-compose.service for scoped ps / down
• Project name defaults to the current directory, overridable via -p or COMPOSE_PROJECT_NAME

examples/compose-example/docker-compose.yml — three-service example (nginx + Node.js API + Redis) exercising ports, volumes, networks, resource limits, build definitions and depends_on.

examples/compose-example/README.md — step-by-step walkthrough: install, up, ps, logs, exec, run, build, down.

docs/container-compose.md — reference page covering supported compose keys, project isolation, and known limitations.

Known limitations (documented)

Feature	Status
Multiple networks per service	Only the first network is attached (container has no network connect)
extra_hosts: host-gateway	Docker-specific alias, skipped with a warning
restart policies	Not yet supported by container run
healthcheck	Not surfaced on container inspect output

Testing

• Tested locally
• Added/updated tests
• Added/updated docs

Unit tests (examples/compose-example/test_container_compose.py) — 61 tests covering all pure functions: _parse_json_lines, _as_list, _label_value, service_container_name, project_name, ordered_services, and build_run_args (image, labels, env, ports, volumes, networks, resources, entrypoint, command, caps, workdir, user, flags).

Run with:

cd examples/compose-example
pip3 install pyyaml --break-system-packages
python3 -m unittest discover -v

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