feat(frontend): scaffold i18n init, fr.json (~140 keys), status map, format helpers

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

frontend/src/i18n/status.ts

@@ -0,0 +1,8 @@
+import i18n from './index';
+import type { EngagementStatus, SimulationStatus } from '@/api/types';
+
+export const engagementStatusLabel = (s: EngagementStatus): string =>
+  i18n.t(`status.engagement.${s}`);
+
+export const simulationStatusLabel = (s: SimulationStatus): string =>
+  i18n.t(`status.simulation.${s}`);