Add Chart Builder: no-JSON Vega-Lite composer from a dataset (M4)

src/app/modals/modal-registry.ts

@@ -16,8 +16,10 @@
 
 import type { ComponentType } from 'react';
 import type { ActiveModal, ModalName } from './types';
+import { ChartBuilderModal } from '../components/ChartBuilderModal';
 import { DatasetsModal } from '../components/DatasetsModal';
 import { ExtractModal } from '../components/ExtractModal';
+import { useChartBuilderStore } from '../stores/ChartBuilderStore';
 import { useDatasetStore } from '../stores/DatasetStore';
 import { useExtractStore } from '../stores/ExtractStore';
 
@@ -62,6 +64,17 @@ export const MODAL_REGISTRY: Partial<Record<ModalName, ModalConfig>> = {
     init: () => useExtractStore.getState().init(),
     getState: () => ({ name: useExtractStore.getState().name }),
   },
+
+  // Opened from a selected dataset's "Build Chart" action; `arg` is its id. Loads
+  // the dataset and pre-populates a smart default config (§06). Applies on Create
+  // (a new snippet), so there is nothing transient to lose on close — no getState.
+  chartBuilder: {
+    name: 'chartBuilder',
+    title: 'Chart Builder',
+    component: ChartBuilderModal,
+    isUrlNavigable: true,
+    init: (datasetId) => useChartBuilderStore.getState().init(datasetId ? Number(datasetId) : null),
+  },
 };
 
 export const getModalConfig = (name: ActiveModal): ModalConfig | undefined =>