feat(23-01): create CopilotKit provider wrapper

- CopilotKitWrapper component configures CopilotKit
- Uses VITE_AGENT_URL env var for endpoint (default localhost:9090)
- Ready to wrap app for AG-UI server connectivity

Author: Alex Holmberg

tests/ag-ui-app/frontend/src/lib/copilotkit.tsx

@@ -0,0 +1,37 @@
+/**
+ * CopilotKit Provider Wrapper
+ *
+ * Configures CopilotKit to connect to the syncable-cli AG-UI server.
+ * The agent endpoint can be customized via VITE_AGENT_URL environment variable.
+ */
+import { CopilotKit } from "@copilotkit/react-core";
+import { ReactNode } from "react";
+
+/**
+ * AG-UI server endpoint.
+ * Default: http://localhost:9090 (local development)
+ * Override with VITE_AGENT_URL environment variable.
+ */
+const AGENT_URL = import.meta.env.VITE_AGENT_URL || "http://localhost:9090";
+
+interface CopilotKitWrapperProps {
+  children: ReactNode;
+}
+
+/**
+ * Wraps the application with CopilotKit provider configured for AG-UI server.
+ *
+ * Usage:
+ * ```tsx
+ * <CopilotKitWrapper>
+ *   <App />
+ * </CopilotKitWrapper>
+ * ```
+ */
+export function CopilotKitWrapper({ children }: CopilotKitWrapperProps) {
+  return (
+    <CopilotKit runtimeUrl={AGENT_URL}>
+      {children}
+    </CopilotKit>
+  );
+}