feat(frontend): zustand stores for settings, lessons, session

packages/frontend/src/main.tsx

@@ -2,8 +2,11 @@ import React from 'react';
 import { createRoot } from 'react-dom/client';
 import { RouterProvider } from 'react-router-dom';
 import { router } from './router.js';
+import { useSettings } from './stores/settingsStore.js';
 import './styles.css';
 
+useSettings.getState().hydrate();
+
 const root = createRoot(document.getElementById('root')!);
 root.render(
   <React.StrictMode>