fix(frontend): translate status badge labels via i18n helpers

StatusBadge and SimulationStatusBadge now call engagementStatusLabel() /
simulationStatusLabel() from @/i18n/status.ts instead of hardcoded English
strings. Tests updated to expect French labels (Planifié/Actif/Clôturé,
En attente/En cours/Révision requise/Terminé).

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

frontend/src/components/StatusBadge.tsx

@@ -1,10 +1,5 @@
 import type { EngagementStatus } from '@/api/types';
-
-const LABELS: Record<EngagementStatus, string> = {
-  planned: 'Planned',
-  active: 'Active',
-  closed: 'Closed',
-};
+import { engagementStatusLabel } from '@/i18n/status';
 
 const STYLES: Record<EngagementStatus, string> = {
   planned: 'bg-warn-soft text-warn border border-warn',
@@ -19,7 +14,7 @@ export function StatusBadge({ status }: { status: EngagementStatus }): JSX.Eleme
       data-testid="status-badge"
       data-status={status}
     >
-      {LABELS[status]}
+      {engagementStatusLabel(status)}
     </span>
   );
 }