script-to-packagelisted

1. Extract the constants block into a `@dataclass Config` with defaults and a `from_args()`/YAML loader. Keep names identical so results are reproducible. 2. Replace literal tokens/keys/paths with `os.environ[...]` and relative `working_directory` paths; fail fast with a clear message if missing. 3. Wrap the body in `main(cfg)`; make loops resumable with a progress file; add `--dry-run` that prints the plan (chunks, batches) without running. 4. Add `pyproject.toml` entry point `zd-<stage>`, a `tests/test_<stage>.py` with one synthetic-input smoke test, and a README section (inputs, outputs, constants table). 5. Run the original and the new version on a small AOI; diff outputs (counts, total area); report.