feat: add initial data node

frontend/src/components/nodes/RenderingNode.tsx

@@ -168,6 +168,16 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
         [nodes, connectedNodeIds]
     )
 
+    const dataSignature = useMemo(
+        () =>
+            nodes
+                .filter((n: any) => n.type === 'data' && connectedNodeIds.has(n.id))
+                .map((n: any) => `${n.id}:${JSON.stringify(n.data?.rows ?? [])}:${JSON.stringify(n.data?.hiddenColumns ?? [])}`)
+                .sort()
+                .join('|'),
+        [nodes, connectedNodeIds]
+    )
+
     const RENDER_DEBOUNCE_MS = 250
 
     useEffect(() => {
@@ -273,6 +283,20 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
                     if (!configIdsUsed.has(e.target)) continue
                     const src = nodes.find((n: any) => n.id === e.source)
                     if (src?.type === 'variable') setVarInContext(src)
+                    if (src?.type === 'data') {
+                        const rows = (src.data?.rows as Record<string, string>[] | undefined) ?? []
+                        const hidden = (src.data?.hiddenColumns as string[] | undefined) ?? []
+                        const visibleCols = (src.data?.columns as string[] | undefined) ?? []
+                            .filter((c) => !hidden.includes(c))
+                        const filteredRows = rows.map((row) => {
+                            const out: Record<string, string> = {}
+                            for (const col of visibleCols) {
+                                if (col in row) out[col] = row[col]
+                            }
+                            return out
+                        })
+                        nunjucksContext[src.id] = filteredRows
+                    }
                 }
                 // All function node ids that feed (directly or transitively) into config — need to register them and collect their variables
                 const functionIdsToRegister = new Set<string>()
@@ -505,7 +529,7 @@ function RenderingNodeComponent({ id, data, width, height, selected }: Props) {
             }
         }
         // Only re-run when inputs that affect the resolved output change (signatures + source). Debounced to avoid excessive re-renders while typing. retryCount triggers re-run on Retry.
-    }, [id, sourceContent, configTypeId, configSignature, edgesSignature, variablesSignature, functionsSignature, viewportWidth, viewportHeight, retryCount])
+    }, [id, sourceContent, configTypeId, configSignature, edgesSignature, variablesSignature, functionsSignature, dataSignature, viewportWidth, viewportHeight, retryCount])
 
     const dimensions =
         width != null && height != null && width > 0 && height > 0