feat: enhance Jira dashboard with export functionality and sprint comparison

- Added export options for CSV and JSON in `JiraDashboardPageClient`, allowing users to download metrics easily.
- Integrated `SprintComparison` component to visualize inter-sprint trends and predictions.
- Updated TODO.md to reflect completion of export metrics and sprint comparison features.

hooks/useJiraExport.ts

@@ -0,0 +1,58 @@
+'use client';
+
+import { useState, useTransition } from 'react';
+import { exportJiraAnalytics, ExportFormat } from '@/actions/jira-export';
+
+export function useJiraExport() {
+  const [isExporting, startTransition] = useTransition();
+  const [error, setError] = useState<string | null>(null);
+
+  const exportAnalytics = (format: ExportFormat = 'csv') => {
+    startTransition(async () => {
+      try {
+        setError(null);
+
+        const result = await exportJiraAnalytics(format);
+
+        if (result.success && result.data && result.filename) {
+          // Créer un blob et déclencher le téléchargement
+          const mimeType = format === 'json' ? 'application/json' : 'text/csv';
+          const blob = new Blob([result.data], { type: mimeType });
+          
+          // Créer un lien temporaire pour le téléchargement
+          const url = window.URL.createObjectURL(blob);
+          const link = document.createElement('a');
+          link.href = url;
+          link.download = result.filename;
+          
+          // Déclencher le téléchargement
+          document.body.appendChild(link);
+          link.click();
+          
+          // Nettoyer
+          document.body.removeChild(link);
+          window.URL.revokeObjectURL(url);
+          
+          console.log(`✅ Export ${format.toUpperCase()} réussi: ${result.filename}`);
+        } else {
+          setError(result.error || 'Erreur lors de l\'export');
+        }
+      } catch (err) {
+        const errorMessage = err instanceof Error ? err.message : 'Erreur lors de l\'export';
+        setError(errorMessage);
+        console.error('Erreur export analytics:', err);
+      }
+    });
+  };
+
+  const exportCSV = () => exportAnalytics('csv');
+  const exportJSON = () => exportAnalytics('json');
+
+  return {
+    isExporting,
+    error,
+    exportCSV,
+    exportJSON,
+    exportAnalytics
+  };
+}