**Data Source Modes** (one required):
- **Connected Table** (`tableWidgetId`) **(recommended)**: Uses data from a connected table widget (e.g., Embedded Search as Table) on the same page. Takes precedence if both are set.
- **Standalone Search** (`search`) **(fallback)**: Uses a configured search query as data source. Use only when no table holds the data to visualize.

**Typical Configuration Workflow**:
1. Choose data source mode:
   - Set `tableWidgetId` to connect to an existing table widget, OR
   - Configure `search` with a search query
2. Select `attributeName` - the attribute to aggregate/group by (only available after data source is configured)
3. Optionally set `title` and `height`