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/metrics.ts

@@ -1,5 +1,5 @@
 import { prisma } from '@/services/core/database';
-import { startOfWeek, endOfWeek, eachDayOfInterval, format, startOfDay, endOfDay } from 'date-fns';
+import { eachDayOfInterval, format, startOfDay, endOfDay, startOfWeek, endOfWeek } from 'date-fns';
 import { fr } from 'date-fns/locale';
 import { formatDateForAPI, getDayName, getToday, subtractDays } from '@/lib/date-utils';
 
@@ -57,11 +57,13 @@ export interface WeeklyMetricsOverview {
 
 export class MetricsService {
   /**
-   * Récupère les métriques journalières de la semaine
+   * Récupère les métriques journalières des 7 derniers jours
    */
   static async getWeeklyMetrics(date: Date = getToday()): Promise<WeeklyMetricsOverview> {
-    const weekStart = startOfWeek(date, { weekStartsOn: 1 }); // Lundi
-    const weekEnd = endOfWeek(date, { weekStartsOn: 1 }); // Dimanche
+    // Fenêtre glissante de 7 jours au lieu de semaine calendaire
+    const weekEnd = new Date(date);
+    const weekStart = new Date(date);
+    weekStart.setDate(weekStart.getDate() - 6); // 7 jours en arrière (incluant aujourd'hui)
     
     // Générer tous les jours de la semaine
     const daysOfWeek = eachDayOfInterval({ start: weekStart, end: weekEnd });