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/tests/StatusBadge.test.tsx

@@ -2,12 +2,18 @@ import { describe, expect, it } from 'vitest';
 import { render, screen } from '@testing-library/react';
 import { StatusBadge } from '@/components/StatusBadge';
 
+const LABELS: Record<string, string> = {
+  planned: 'Planifié',
+  active: 'Actif',
+  closed: 'Clôturé',
+};
+
 describe('StatusBadge', () => {
   it.each(['planned', 'active', 'closed'] as const)('renders %s label and data attr', (status) => {
     render(<StatusBadge status={status} />);
     const badge = screen.getByTestId('status-badge');
     expect(badge).toHaveAttribute('data-status', status);
-    expect(badge.textContent?.toLowerCase()).toBe(status);
+    expect(badge.textContent).toBe(LABELS[status]);
   });
 
   it('applies warn-soft surface for planned', () => {