refactor: enhance date handling across components

- Replaced direct date manipulations with utility functions for consistency and readability.
- Updated date formatting in `DailyCalendar`, `RecentTasks`, `CompletionRateChart`, and other components to use `formatDateShort` and `formatDateForDisplay`.
- Improved date parsing in `JiraLogs`, `JiraSchedulerConfig`, and `BackupSettingsPageClient` to ensure proper handling of date strings.
- Streamlined date initialization in `useDaily` and `DailyService` to utilize `getToday` and `getYesterday` for better clarity.

src/services/jira.ts

@@ -5,7 +5,7 @@
 
 import { JiraTask } from '@/lib/types';
 import { prisma } from './database';
-import { parseDate } from '@/lib/date-utils';
+import { parseDate, formatDateForDisplay } from '@/lib/date-utils';
 
 export interface JiraConfig {
   baseUrl: string;
@@ -389,8 +389,8 @@ export class JiraService {
         changes.push(`Priorité: préservée localement (${existingTask.priority})`);
       }
       if ((existingTask.dueDate?.getTime() || null) !== (taskData.dueDate?.getTime() || null)) {
-        const oldDate = existingTask.dueDate ? existingTask.dueDate.toLocaleDateString() : 'Aucune';
-        const newDate = taskData.dueDate ? taskData.dueDate.toLocaleDateString() : 'Aucune';
+        const oldDate = existingTask.dueDate ? formatDateForDisplay(existingTask.dueDate) : 'Aucune';
+        const newDate = taskData.dueDate ? formatDateForDisplay(taskData.dueDate) : 'Aucune';
         changes.push(`Échéance: ${oldDate} → ${newDate}`);
       }
       if (existingTask.jiraProject !== taskData.jiraProject) {