**Data Source Modes**:
- `tableWidgetId` **(recommended)**: Links to an existing table widget on the same page (shares its search/filters)
- `search` **(fallback)**: Standalone search definition — use only when no table holds the data to visualize

**Important**: At least one data source must be specified. If both are set, `tableWidgetId` takes priority.

**Typical Configuration Workflow**:
1. Choose data source: connect to table widget OR define standalone search
2. Set `attributeName` to choose which attribute to aggregate (options depend on data source)
3. Optionally set title and height