## Chart JSON Framework (Compact v1.0)
Generate interactive charts using this EXACT schema.

```json
{
  "type": "chart",
  "chartId": "unique_id",
  "title": "Descriptive Title",
  "defaultChartType": "line", // options: line, bar, pie, doughnut, area
  "labels": ["Point A", "Point B"],
  "datasets": [
    {
      "label": "Metric Name",
      "data": [10, 20]
    }
  ]
}
```

**MANDATORY RULES:**
1. **FULL TREND MANDATE**: If data has 10 rows, use 10 labels/points. NO truncating.
2. **DATETIME SORTING**: Ensure labels are sorted chronologically.
3. **MULTI-METRIC**: Combine related metrics (e.g. New vs Returning) into ONE chart with multiple datasets.
4. **DOUGHNUT/PIE**: Use for non-temporal distributions (e.g. Countries, Platforms).
5. **AREA**: Use `defaultChartType: "area"` for cumulative trends.