feat(studio): promote to variable from the design panel

packages/studio/src/components/DesignPanelPromoteProvider.tsx

@@ -0,0 +1,31 @@
+/**
+ * Wires the Design panel's promote-to-variable context: instantiates the
+ * single-writer variables persist path and feeds it to VariablePromoteProvider,
+ * so schema edits from Design-panel controls (declare + bind, or edit a bound
+ * variable's default) flow through the same path the Variables tab uses.
+ */
+
+import type { ReactNode } from "react";
+import type { DomEditSelection } from "./editor/domEditingTypes";
+import { useVariablesPersist, type UseVariablesPersistParams } from "../hooks/useVariablesPersist";
+import { VariablePromoteProvider } from "../contexts/VariablePromoteContext";
+
+export function DesignPanelPromoteProvider({
+  selection,
+  children,
+  ...persistParams
+}: UseVariablesPersistParams & {
+  selection: DomEditSelection | null;
+  children: ReactNode;
+}) {
+  const persist = useVariablesPersist(persistParams);
+  return (
+    <VariablePromoteProvider
+      session={persistParams.sdkSession}
+      selection={selection}
+      persist={persist}
+    >
+      {children}
+    </VariablePromoteProvider>
+  );
+}