Stream the rendered report file using the format and sheet stored on the report at creation.

format is required: it must be supplied on the original POST /reports/* request for this endpoint to return a file. For multi-sheet reports (e.g. Payroll Register), sheet must also be supplied on the POST when a specific sheet is wanted. Request-side hints (Accept header, ?sheet= query param) are ignored here.

Returns 422 when format was not stored on the report, and 404 when the report's results have not yet been generated.