feat(editor): suggest declared array locals in array-name autocomplete

The flow-array-names datalist (used by the export-CSV node columns and the
legacy accumulate/clear nodes) was sourced only from array names already
referenced by other nodes, so a freshly declared array local would not appear
as an autocomplete suggestion until it was typed somewhere. Seed the datalist
with declared array statevars first, then node-referenced names.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

web/src/LogicEditor.tsx

@@ -577,9 +577,13 @@ export default function LogicEditor({ graph, onChange, widgets = [], statevars,
 
   // Array names already referenced by accumulate/export/clear nodes, offered as
   // autocomplete suggestions so the same array is reused across nodes.
-  const arrayNames = Array.from(new Set(
-    nodes.map(n => n.params.array).filter((a): a is string => !!a)
-  ));
+  // Suggestions for the array-name autocomplete (export columns, accumulate,
+  // clear): declared array locals first, then any names already referenced by
+  // nodes (covers legacy/in-flight names not yet declared).
+  const arrayNames = Array.from(new Set([
+    ...(statevars ?? []).filter(v => v.type === 'array').map(v => v.name),
+    ...nodes.map(n => n.params.array).filter((a): a is string => !!a),
+  ]));
 
   // Append a {ds:name} reference into a node's expression field.
   function insertRef(id: string, field: string, ds: string, sig: string) {