Computes on-demand battery charge/discharge forecasts for the given time range [fromDate, toDate). The request body is optional: supply custom electricity prices to override the defaults, or omit them to fall back to EPEX day-ahead prices (same as the GET endpoint). Optionally filter strategies in the request body; omit to compute all supported strategies. Query dates may include a timezone offset; timestamps in the response use UTC (+00:00). Requires battery charge state updated within the last 60 minutes.