feat: update settings page and theme context for user preferences

- Replaced `SettingsPageClient` with `SettingsIndexPageClient` to fetch and display user preferences on the settings page.
- Integrated `userPreferencesService` to retrieve all preferences asynchronously, enhancing data handling.
- Refactored theme management in `ThemeContext` to use `updateViewPreferences` for saving theme changes, improving error handling and user feedback.
- Marked the task for creating dedicated config sub-pages as complete in TODO.md.

src/app/settings/general/page.tsx

@@ -0,0 +1,12 @@
+import { userPreferencesService } from '@/services/user-preferences';
+import { GeneralSettingsPageClient } from '@/components/settings/GeneralSettingsPageClient';
+
+// Force dynamic rendering for real-time data
+export const dynamic = 'force-dynamic';
+
+export default async function GeneralSettingsPage() {
+  // Fetch data server-side
+  const preferences = await userPreferencesService.getAllPreferences();
+
+  return <GeneralSettingsPageClient initialPreferences={preferences} />;
+}