style(design): apply Minimal Dark Mode design system\n\n- Switched to complete Dark Mode (OLED-friendly)\n- Established standard color palette matching modern technical aesthetics\n- Changed font to Plus Jakarta Sans for increased legibility\n- Enforced dark mode as default in App.tsx\n- Fixed several React cascading render (setState in useEffect) warnings

src/App.tsx

@@ -1,38 +1,38 @@
-import { useEffect } from 'react';
-import { createRoot } from 'react-dom/client';
-import { syncWithLocalTheme } from './actions/theme';
-import { useTranslation } from 'react-i18next';
-import { updateAppLanguage } from './actions/language';
-import { RouterProvider } from '@tanstack/react-router';
-import { router } from './utils/routes';
-import './localization/i18n';
-import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
-import { ThemeProvider } from '@/components/theme-provider';
-import { Toaster } from '@/components/ui/toaster';
-import { LOCAL_STORAGE_KEYS } from '@/constants';
-
-function App() {
-  const { i18n } = useTranslation();
-
-  useEffect(() => {
-    syncWithLocalTheme();
-    updateAppLanguage(i18n);
-    if (window.electron?.changeLanguage) {
-      window.electron.changeLanguage(i18n.language);
-    }
-  }, [i18n]);
-
-  return <RouterProvider router={router} />;
-}
-
-const queryClient = new QueryClient();
-
-const root = createRoot(document.getElementById('app')!);
-root.render(
-  <QueryClientProvider client={queryClient}>
-    <ThemeProvider storageKey={LOCAL_STORAGE_KEYS.THEME} defaultTheme="system">
-      <App />
-      <Toaster />
-    </ThemeProvider>
-  </QueryClientProvider>,
-);
+import { useEffect } from 'react';
+import { createRoot } from 'react-dom/client';
+import { syncWithLocalTheme } from './actions/theme';
+import { useTranslation } from 'react-i18next';
+import { updateAppLanguage } from './actions/language';
+import { RouterProvider } from '@tanstack/react-router';
+import { router } from './utils/routes';
+import './localization/i18n';
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query';
+import { ThemeProvider } from '@/components/theme-provider';
+import { Toaster } from '@/components/ui/toaster';
+import { LOCAL_STORAGE_KEYS } from '@/constants';
+
+function App() {
+  const { i18n } = useTranslation();
+
+  useEffect(() => {
+    syncWithLocalTheme();
+    updateAppLanguage(i18n);
+    if (window.electron?.changeLanguage) {
+      window.electron.changeLanguage(i18n.language);
+    }
+  }, [i18n]);
+
+  return <RouterProvider router={router} />;
+}
+
+const queryClient = new QueryClient();
+
+const root = createRoot(document.getElementById('app')!);
+root.render(
+  <QueryClientProvider client={queryClient}>
+    <ThemeProvider storageKey={LOCAL_STORAGE_KEYS.THEME} defaultTheme="dark">
+      <App />
+      <Toaster />
+    </ThemeProvider>
+  </QueryClientProvider>,
+);