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/contexts/ThemeContext.tsx

@@ -1,7 +1,7 @@
 'use client';
 
 import { createContext, useContext, useEffect, useState, ReactNode } from 'react';
-import { userPreferencesClient } from '@/clients/user-preferences-client';
+import { updateViewPreferences } from '@/actions/preferences';
 
 type Theme = 'light' | 'dark';
 
@@ -38,11 +38,14 @@ export function ThemeProvider({ children, initialTheme = 'dark' }: ThemeProvider
     const newTheme = theme === 'dark' ? 'light' : 'dark';
     setThemeState(newTheme);
     
-    // Sauvegarder en base de façon asynchrone via le client
+    // Sauvegarder en base de façon asynchrone via server action
     try {
-      await userPreferencesClient.updateViewPreferences({
+      const result = await updateViewPreferences({
         theme: newTheme
       });
+      if (!result.success) {
+        console.error('Erreur lors de la sauvegarde du thème:', result.error);
+      }
     } catch (error) {
       console.error('Erreur lors de la sauvegarde du thème:', error);
     }
@@ -51,11 +54,14 @@ export function ThemeProvider({ children, initialTheme = 'dark' }: ThemeProvider
   const setTheme = async (newTheme: Theme) => {
     setThemeState(newTheme);
     
-    // Sauvegarder en base de façon asynchrone via le client
+    // Sauvegarder en base de façon asynchrone via server action
     try {
-      await userPreferencesClient.updateViewPreferences({
+      const result = await updateViewPreferences({
         theme: newTheme
       });
+      if (!result.success) {
+        console.error('Erreur lors de la sauvegarde du thème:', result.error);
+      }
     } catch (error) {
       console.error('Erreur lors de la sauvegarde du thème:', error);
     }