refactor: simplify BoardContainer and update task management

- Removed initialTasks and initialStats props from KanbanBoardContainer, now using TasksContext for task management.
- Updated useTasks hook to include a simulated delay for sync indicator during task updates.
- Replaced KanbanBoardContainer with HomePageClient in the HomePage component for a cleaner structure.

hooks/useTasks.ts

@@ -162,6 +162,9 @@ export function useTasks(
 
     // 3. Appel API en arrière-plan
     try {
+      // Délai artificiel pour voir l'indicateur de sync (à supprimer en prod)
+      await new Promise(resolve => setTimeout(resolve, 1000));
+      
       const response = await tasksClient.updateTask(data);
       
       // Si l'API retourne des données différentes, on met à jour