feat: integrate ToastProvider and enhance theme management

- Added `ToastProvider` to `RootLayout` for improved user feedback on theme changes.
- Updated `ThemeProvider` to display toast notifications with theme names and icons upon theme changes.
- Refactored theme-related imports to streamline code and improve maintainability.
- Simplified background cycling logic in `useBackgroundCycle` to utilize centralized background definitions.
- Cleaned up unused background definitions in `BackgroundContext` for better clarity and performance.

src/hooks/useBackgroundCycle.ts

@@ -1,66 +1,25 @@
 'use client';
 
 import { useUserPreferences } from '@/contexts/UserPreferencesContext';
-
-// Liste des backgrounds prédéfinis pour le cycle
-const BACKGROUND_CYCLE = [
-  'none',
-  'theme-subtle', 
-  'theme-primary',
-  'theme-accent',
-  'theme-success',
-  'theme-purple',
-  'theme-diagonal',
-  'theme-radial',
-  'theme-sunset',
-  'theme-ocean',
-  'theme-forest',
-  'theme-galaxy'
-];
+import { useToast } from '@/components/ui/Toast';
+import { BACKGROUND_NAMES, TOAST_ICONS, getNextBackground } from '@/lib/ui-config';
 
 export function useBackgroundCycle() {
   const { preferences, updateViewPreferences } = useUserPreferences();
+  const { showToast } = useToast();
 
   const cycleBackground = () => {
     const currentBackground = preferences?.viewPreferences?.backgroundImage;
     const customImages = preferences?.viewPreferences?.customImages || [];
     
-    // Construire la liste complète des backgrounds (prédéfinis + personnalisés)
-    const allBackgrounds = [...BACKGROUND_CYCLE];
-    
-    // Ajouter toutes les images personnalisées
-    customImages.forEach(url => {
-      if (!allBackgrounds.includes(url)) {
-        allBackgrounds.push(url);
-      }
-    });
-
-    const currentIndex = allBackgrounds.findIndex(bg => bg === currentBackground);
-    
-    // Si on ne trouve pas l'index, c'est qu'on est sur "none" (undefined)
-    // Dans ce cas, on commence au début de la liste
-    let actualCurrentIndex = currentIndex;
-    if (currentIndex === -1) {
-      actualCurrentIndex = -1; // On est sur "none", on va commencer à l'index 0
-    }
-    
-    const nextIndex = (actualCurrentIndex + 1) % allBackgrounds.length;
-    const nextBackground = allBackgrounds[nextIndex];
-    
-    // Si c'est 'none', on met undefined
+    const nextBackground = getNextBackground(currentBackground || 'none', customImages);
     const backgroundImage = nextBackground === 'none' ? undefined : nextBackground;
     
-    // Si on est sur "none" (undefined) et qu'on va vers "none", on va vers le suivant
-    if (currentBackground === undefined && nextBackground === 'none') {
-      const nextNextIndex = (nextIndex + 1) % allBackgrounds.length;
-      const nextNextBackground = allBackgrounds[nextNextIndex];
-      const finalBackgroundImage = nextNextBackground === 'none' ? undefined : nextNextBackground;
-      
-      updateViewPreferences({ backgroundImage: finalBackgroundImage });
-      return;
-    }
-    
     updateViewPreferences({ backgroundImage });
+    
+    // Afficher le toast avec le nom du background
+    const backgroundName = BACKGROUND_NAMES[nextBackground] || 'Image personnalisée';
+    showToast(`Background: ${backgroundName}`, 2000, TOAST_ICONS.background);
   };
 
   return {