Fix local dev API wiring and theme default

src/App.tsx

@@ -570,15 +570,19 @@ function UsersTab({
 }
 
 export default function App() {
-  const [preferences, setPreferences] = useState<PanelPreferences>(() => loadPanelPreferences());
+  const [preferences, setPreferences] = useState<PanelPreferences>(() => {
+    const loaded = loadPanelPreferences();
+    applyPanelTheme(loaded.theme);
+    return loaded;
+  });
   const [session, setSession] = useState<StoredSession | null>(() => loadStoredSession());
   const [activeTab, setActiveTab] = useState<TabId>('dashboard');
   const [snapshot, setSnapshot] = useState<DashboardSnapshot>(fallbackDashboardSnapshot);
   const text = getPanelText(preferences.language);
 
   useEffect(() => {
-    applyPanelTheme(preferences.theme);
     savePanelPreferences(preferences);
+    applyPanelTheme(preferences.theme);
   }, [preferences]);
 
   useEffect(() => {

src/lib/panelPreferences.ts

@@ -10,7 +10,7 @@ const PREFERENCES_KEY = '3proxy-ui-panel-preferences-v2';
 
 export const defaultPanelPreferences: PanelPreferences = {
   language: 'en',
-  theme: 'light',
+  theme: 'system',
 };
 
 export function loadPanelPreferences(): PanelPreferences {