List the artifacts attached to a build or a specific job, then download an artifact's contents via the REST API's redirect-based download endpoint.

Documented steps

1. Authenticate with `Authorization: Bearer $TOKEN`. List/get/download require scope `read_artifacts`; deleting requires `write_artifacts`. See https://buildkite.com/docs/apis/rest-api/artifacts
2. List artifacts for a whole build (all jobs): `GET https://api.buildkite.com/v2/organizations/{org.slug}/pipelines/{pipeline.slug}/builds/{build.number}/artifacts` — this route needs the build **number** (e.g. `3`), not the build UUID. Optional query params: `state` (`new`|`error`|`finished`|`deleted`|`expired`, else `422`) and `path` (exact match or glob with `*`).
3. List artifacts for one job: `GET https://api.buildkite.com/v2/organizations/{org.slug}/jobs/{job.id}/artifacts`, or the build-scoped equivalent `GET .../pipelines/{pipeline.slug}/builds/{build.number}/jobs/{job.id}/artifacts`.
4. Get a single artifact's metadata: `GET .../jobs/{job.id}/artifacts/{id}` (or the build-scoped path). Each artifact record includes a `download_url` you can call directly.
5. Download: `GET .../jobs/{job.id}/artifacts/{id}/download` (or the build-scoped variant). Responds `302 Found`; the pre-signed storage URL is returned BOTH in the JSON body as `{"url": "..."}` and in the `Location` header — follow the redirect (e.g. `curl -L`) or fetch that URL immediately.
6. Delete an artifact record: `DELETE .../jobs/{job.id}/artifacts/{id}` (or build-scoped) — scope `write_artifacts`, returns `204 No Content`.
7. Docs used: https://buildkite.com/docs/apis/rest-api/artifacts