Returns results for a completed forecast run at the requested resolution.

Results are returned in column-oriented format: each entry in columns has a label, a display_label, and a data array of length periods. Timestamps are implicit — derive them from data_start, the resolution, and the array index.

Use ?columns= to request a subset of columns by label. Omit the parameter to return all available columns.

Returns 404 if the run has not yet completed. Poll GET /runs/{id}/ until status is ready_for_review before calling this endpoint.