feat: add pinned tag functionality and UI enhancements

- Introduced `isPinned` property to the `Tag` model for marking main objectives.
- Updated `TagForm` to include a checkbox for setting tags as pinned, enhancing user interaction.
- Enhanced `KanbanBoardContainer` to display pinned tasks in a dedicated `ObjectivesBoard`, improving task visibility.
- Modified `KanbanFilters` to support filtering by pinned tags, streamlining task management.
- Adjusted `TasksContext` to separate pinned tasks from regular tasks for better organization.

components/kanban/BoardContainer.tsx

@@ -3,6 +3,7 @@
 import { useState } from 'react';
 import { KanbanBoard } from './Board';
 import { SwimlanesBoard } from './SwimlanesBoard';
+import { ObjectivesBoard } from './ObjectivesBoard';
 import { KanbanFilters } from './KanbanFilters';
 import { EditTaskForm } from '@/components/forms/EditTaskForm';
 import { useTasksContext } from '@/contexts/TasksContext';
@@ -12,13 +13,15 @@ import { UpdateTaskData } from '@/clients/tasks-client';
 export function KanbanBoardContainer() {
   const { 
     filteredTasks, 
+    pinnedTasks,
     loading, 
     createTask, 
     deleteTask, 
     updateTask, 
     updateTaskOptimistic,
     kanbanFilters,
-    setKanbanFilters
+    setKanbanFilters,
+    tags
   } = useTasksContext();
 
   const [editingTask, setEditingTask] = useState<Task | null>(null);
@@ -47,6 +50,9 @@ export function KanbanBoardContainer() {
     });
   };
 
+  // Obtenir le nom du tag épinglé pour l'affichage
+  const pinnedTagName = tags.find(tag => tag.isPinned)?.name;
+
   return (
     <>
       <KanbanFilters
@@ -54,6 +60,18 @@ export function KanbanBoardContainer() {
         onFiltersChange={setKanbanFilters}
       />
       
+      {/* Section Objectifs Principaux */}
+      {pinnedTasks.length > 0 && (
+        <ObjectivesBoard
+          tasks={pinnedTasks}
+          onDeleteTask={deleteTask}
+          onEditTask={handleEditTask}
+          onUpdateTitle={handleUpdateTitle}
+          compactView={kanbanFilters.compactView}
+          pinnedTagName={pinnedTagName}
+        />
+      )}
+      
       {kanbanFilters.swimlanesByTags ? (
         <SwimlanesBoard 
           tasks={filteredTasks}