Extending ciz

ciz is designed so new commands, stages, and runtime capabilities can be added without collapsing the planner architecture.

Add a new CLI command

Follow the existing command pattern under cmd/ciz:

1. keep Cobra wiring in a dedicated command_*.go file
2. place business logic in internal/*
3. reuse existing stage packages instead of duplicating parsing or normalization

That keeps the command layer readable and testable.

Extend the planner

Prefer changes that preserve the current package contracts:

• internal/model stays the stage contract
• expand remains a pure transformation from normalized input to component instances
• render remains deterministic and side-effect free except for file writing

Add a new runner backend

Execution backends live behind the executor interface in internal/executor.

When adding a backend:

1. implement the executor methods
2. register the backend in the executor registry
3. document backend-specific semantics in the runtime docs
4. add tests for preparation, step execution, and cleanup behavior

Typical extension ideas

• graph output for richer DAG visualizations
• lint for policy-only validation passes
• new composition types for additional platform domains
• extra execution backends when the current local, Docker, and GitHub Actions set is not enough