fix(skills): regenerate the react-blocks contract for the combo chart type

Fifth generated artefact tracking the spec surface: the react-blocks
contract and its reference table inline the ChartType union.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

Author: os-zhuang

skills/objectstack-ui/contracts/react-blocks.contract.json

@@ -322,7 +322,7 @@
         },
         {
           "name": "type",
-          "type": "'bar' | 'horizontal-bar' | 'column' | 'line' | 'area' | 'pie' | 'donut' | 'funnel' | 'scatter' | 'treemap' | 'sankey' | 'gauge' | 'solid-gauge' | 'metric' | 'kpi' | 'bullet' | 'radar' | 'table' | 'pivot'",
+          "type": "'bar' | 'horizontal-bar' | 'column' | 'line' | 'area' | 'pie' | 'donut' | 'funnel' | 'scatter' | 'treemap' | 'sankey' | 'combo' | 'gauge' | 'solid-gauge' | 'metric' | 'kpi' | 'bullet' | 'radar' | 'table' | 'pivot'",
           "kind": "data",
           "required": true,
           "description": ""

skills/objectstack-ui/references/react-blocks.md

@@ -73,7 +73,7 @@ Chart over an object’s aggregated data. Bind objectName + aggregate; the axes
 | `aggregate` | `{ field?: string; function: 'count' \| 'sum' \| 'avg' \| 'min' \| 'max'; groupBy: string \| { field: string; dateGranularity?: 'day' \| 'week' \| 'month' \| 'quarter' \| 'year' } }` | binding |  | Aggregation run against objectName. Result rows are keyed by the RAW FIELD NAMES: one column named after groupBy (the category) and one named after field (the value; the literal "count" for a fieldless count). Bind xAxis.field / yAxis[].field / series[].name to those names. |
 | `data` | `any[]` | binding |  | Static/precomputed data to chart directly instead of binding via objectName + aggregate. |
 | `filter` | `FilterArray` | controlled |  | ObjectQL filter scoping the data; drive from React state. |
-| `type` | `'bar' \| 'horizontal-bar' \| 'column' \| 'line' \| 'area' \| 'pie' \| 'donut' \| 'funnel' \| 'scatter' \| 'treemap' \| 'sankey' \| 'gauge' \| 'solid-gauge' \| 'metric' \| 'kpi' \| 'bullet' \| 'radar' \| 'table' \| 'pivot'` | data | ✓ |  |
+| `type` | `'bar' \| 'horizontal-bar' \| 'column' \| 'line' \| 'area' \| 'pie' \| 'donut' \| 'funnel' \| 'scatter' \| 'treemap' \| 'sankey' \| 'combo' \| 'gauge' \| 'solid-gauge' \| 'metric' \| 'kpi' \| 'bullet' \| 'radar' \| 'table' \| 'pivot'` | data | ✓ |  |
 | `title` | `string` | data |  | Chart title |
 | `subtitle` | `string` | data |  | Chart subtitle |
 | `description` | `string` | data |  | Accessibility description — announced to screen readers as the chart’s label |