Start an export of your organization's data

Start a background export of your organization's data and return a task id. Poll GET /v2/data-export/{task_id} until it succeeds to get a short-lived download URL for the permit-org-export-<org>-<ts>.tar.gz (one data/<table>.csv per table + manifest.json).

Requires an Organization API key with ADMIN access; write/read-only keys are rejected. The organization is taken from the key, so this only ever exports your own organization. The archive contains your plaintext API-key secrets (so a self-hosted import keeps working without re-issuing keys) — treat the download URL and the file as credentials.