fix: remove unused React import and add aria-current to SettingsSidebar

app/components/SettingsSidebar.tsx

@@ -1,5 +1,3 @@
-import React from "react";
-
 export type SettingsSection = "llm" | "trading" | "stocks" | "system";
 
 interface SettingsSidebarProps {
@@ -24,6 +22,7 @@ export default function SettingsSidebar({ activeSection, onSectionChange }: Sett
             <button
               key={section.id}
               onClick={() => onSectionChange(section.id)}
+              aria-current={activeSection === section.id ? "page" : undefined}
               className={`w-full flex items-center gap-3 px-3 py-2.5 rounded-lg text-sm font-medium transition-colors ${
                 activeSection === section.id
                   ? "bg-blue-50 text-blue-700 border-l-4 border-blue-600"