Archive a workflow

Soft-deletes a workflow by moving it from any non-archived state to archived. Archived workflows stop responding to trigger events immediately, become read-only, and are excluded from list responses unless requested with filter[status][in]=archived. Their runs, version history, and definition are preserved, and the workflow can be restored with POST /api/v3/workflows/{workflowId}/unarchive. Archiving an already archived workflow returns 422 with code invalid_workflow_state.