feat: update dashboard components and analytics for 7-day summaries

- Modified `ManagerWeeklySummary`, `MetricsTab`, and `ProductivityAnalytics` to reflect a focus on the last 7 days instead of the current week.
- Enhanced `ManagerSummaryService` and `MetricsService` to calculate metrics over a sliding 7-day window, improving data relevance.
- Added a new utility function `formatDistanceToNow` for better date formatting in French.
- Updated comments and documentation to clarify changes in timeframes.

src/services/analytics/analytics.ts

@@ -13,6 +13,8 @@ export interface ProductivityMetrics {
     week: string;
     completed: number;
     average: number;
+    weekNumber?: number;
+    weekStart?: Date;
   }>;
   priorityDistribution: Array<{
     priority: string;
@@ -137,35 +139,41 @@ export class AnalyticsService {
    * Calcule la vélocité (tâches terminées par semaine)
    */
   private static calculateVelocity(tasks: Task[], start: Date, end: Date) {
-    const weeklyData: Array<{ week: string; completed: number; average: number }> = [];
+    const weeklyData: Array<{ week: string; completed: number; average: number; weekNumber: number; weekStart: Date }> = [];
     const completedTasks = tasks.filter(task => task.completedAt);
     
-    // Grouper par semaine
-    const weekGroups = new Map<string, number>();
+    // Grouper par semaine en utilisant le numéro de semaine comme clé
+    const weekGroups = new Map<number, { count: number; weekStart: Date }>();
     
     completedTasks.forEach(task => {
       if (task.completedAt && task.completedAt >= start && task.completedAt <= end) {
         const weekStart = this.getWeekStart(task.completedAt);
-        const weekKey = weekStart.toISOString().split('T')[0];
-        weekGroups.set(weekKey, (weekGroups.get(weekKey) || 0) + 1);
+        const weekNumber = this.getWeekNumber(weekStart);
+        
+        if (!weekGroups.has(weekNumber)) {
+          weekGroups.set(weekNumber, { count: 0, weekStart });
+        }
+        weekGroups.get(weekNumber)!.count++;
       }
     });
     
     // Calculer la moyenne mobile
-    const values = Array.from(weekGroups.values());
+    const values = Array.from(weekGroups.values()).map(w => w.count);
     const average = values.length > 0 ? values.reduce((a, b) => a + b, 0) / values.length : 0;
     
     // Convertir en format pour le graphique
-    weekGroups.forEach((count, weekKey) => {
-      const weekDate = parseDate(weekKey);
+    weekGroups.forEach((data, weekNumber) => {
       weeklyData.push({
-        week: `Sem. ${this.getWeekNumber(weekDate)}`,
-        completed: count,
-        average: Math.round(average * 10) / 10
+        week: `Sem. ${weekNumber}`,
+        completed: data.count,
+        average: Math.round(average * 10) / 10,
+        weekNumber,
+        weekStart: data.weekStart
       });
     });
     
-    return weeklyData.sort((a, b) => a.week.localeCompare(b.week));
+    // Trier par numéro de semaine (pas alphabétiquement)
+    return weeklyData.sort((a, b) => a.weekNumber - b.weekNumber);
   }
 
   /**