feat: add swimlane mode selection to KanbanFilters and BoardContainer

- Introduced `swimlanesMode` in `KanbanFilters` to toggle between 'tags' and 'priority' swimlanes.
- Updated `KanbanBoardContainer` to conditionally render `PrioritySwimlanesBoard` based on the selected mode.
- Enhanced UI to include dropdown for swimlane mode selection, improving user experience in task organization.
- Adjusted `TasksContext` to persist swimlane mode preferences, ensuring consistent behavior across sessions.

src/contexts/TasksContext.tsx

@@ -73,7 +73,8 @@ export function TasksProvider({ children, initialTasks, initialStats, initialTag
       showCompleted: savedFilters.showCompleted,
       sortBy: savedFilters.sortBy || createSortKey('priority', 'desc'), // Tri par défaut
       compactView: savedViewPrefs.compactView,
-      swimlanesByTags: savedViewPrefs.swimlanesByTags
+      swimlanesByTags: savedViewPrefs.swimlanesByTags,
+      swimlanesMode: savedViewPrefs.swimlanesMode || 'tags'
     });
   }, []);
 
@@ -94,6 +95,7 @@ export function TasksProvider({ children, initialTasks, initialStats, initialTag
     userPreferencesService.saveViewPreferences({
       compactView: newFilters.compactView || false,
       swimlanesByTags: newFilters.swimlanesByTags || false,
+      swimlanesMode: newFilters.swimlanesMode || 'tags',
       showObjectives: true // Toujours visible pour l'instant
     });
   };