Update existing simulation_worker unit tests to account for new _prepare_data integration:
- Mock _prepare_data to return available dates
- Update mock executors to return proper result dicts with model/date fields
Note: Some tests need additional work to properly verify job status updates.
Co-Authored-By: Claude <noreply@anthropic.com>
Orchestrate data preparation phase:
- Check missing data
- Download if needed
- Filter completed dates
- Update job status
Co-Authored-By: Claude <noreply@anthropic.com>