feat(frontend): i18n engagement pages (list, detail, form) + fr-FR date formatting

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

frontend/src/pages/EngagementsListPage.tsx

@@ -1,5 +1,6 @@
 import { Link } from 'react-router-dom';
 import { Plus } from 'lucide-react';
+import { useTranslation } from 'react-i18next';
 import { extractApiError } from '@/api/client';
 import type { Engagement } from '@/api/types';
 import { useDeleteEngagement, useEngagementsList } from '@/hooks/useEngagements';
@@ -9,25 +10,22 @@ import { LoadingState } from '@/components/LoadingState';
 import { ErrorState } from '@/components/ErrorState';
 import { EmptyState } from '@/components/EmptyState';
 import { StatusBadge } from '@/components/StatusBadge';
-
-function formatDate(value: string | null): string {
-  if (!value) return '—';
-  return value;
-}
+import { formatDate } from '@/lib/format';
 
 export function EngagementsListPage(): JSX.Element {
+  const { t } = useTranslation();
   const { data, isLoading, isError, error, refetch } = useEngagementsList();
   const { canEditEngagements } = useAuth();
   const { push } = useToast();
   const deleteMutation = useDeleteEngagement();
 
   const onDelete = async (eng: Engagement) => {
-    if (!window.confirm(`Delete engagement "${eng.name}"? This cannot be undone.`)) return;
+    if (!window.confirm(t('engagement.list.deleteConfirm', { name: eng.name }))) return;
     try {
       await deleteMutation.mutateAsync(eng.id);
-      push('Engagement deleted', 'success');
+      push(t('engagement.list.toast.deleted'), 'success');
     } catch (err) {
-      push(extractApiError(err, 'Could not delete engagement'), 'error');
+      push(extractApiError(err, t('engagement.list.error.delete')), 'error');
     }
   };
 
@@ -35,32 +33,32 @@ export function EngagementsListPage(): JSX.Element {
     <div className="flex flex-col gap-xl">
       <header className="flex items-end justify-between gap-md">
         <div>
-          <h1 className="text-[32px] font-medium leading-none">Engagements</h1>
+          <h1 className="text-[32px] font-medium leading-none">{t('engagement.list.title')}</h1>
           <p className="text-charcoal text-[16px] mt-sm">
-            Red team missions and their lifecycle status.
+            {t('engagement.list.subtitle')}
           </p>
         </div>
         {canEditEngagements ? (
           <Link to="/engagements/new" className="btn-primary">
-            <Plus size={14} aria-hidden /> New
+            <Plus size={14} aria-hidden /> {t('engagement.list.new')}
           </Link>
         ) : null}
       </header>
 
-      {isLoading ? <LoadingState label="Loading engagements…" /> : null}
+      {isLoading ? <LoadingState label={t('common.loading')} /> : null}
 
       {isError ? (
-        <ErrorState message={extractApiError(error, 'Could not load engagements')} onRetry={() => refetch()} />
+        <ErrorState message={extractApiError(error, t('engagement.list.error.load'))} onRetry={() => refetch()} />
       ) : null}
 
       {!isLoading && !isError && data && data.length === 0 ? (
         <EmptyState
-          title="No engagements yet"
-          description="Create your first engagement to start tracking red team missions."
+          title={t('engagement.list.empty.title')}
+          description={t('engagement.list.empty.desc')}
           action={
             canEditEngagements ? (
               <Link to="/engagements/new" className="btn-primary">
-                <Plus size={14} aria-hidden /> New
+                <Plus size={14} aria-hidden /> {t('engagement.list.new')}
               </Link>
             ) : undefined
           }
@@ -72,12 +70,12 @@ export function EngagementsListPage(): JSX.Element {
           <table className="table-compact w-full text-left">
             <thead className="bg-cloud border-b border-hairline">
               <tr>
-                <th>Name</th>
-                <th>Status</th>
-                <th>Start</th>
-                <th>End</th>
-                <th>Created by</th>
-                <th className="text-right">Actions</th>
+                <th>{t('engagement.list.col.name')}</th>
+                <th>{t('engagement.list.col.status')}</th>
+                <th>{t('engagement.list.col.start')}</th>
+                <th>{t('engagement.list.col.end')}</th>
+                <th>{t('engagement.list.col.createdBy')}</th>
+                <th className="text-right">{t('engagement.list.col.actions')}</th>
               </tr>
             </thead>
             <tbody>
@@ -97,12 +95,12 @@ export function EngagementsListPage(): JSX.Element {
                   <td className="text-right">
                     <div className="inline-flex gap-sm">
                       <Link to={`/engagements/${eng.id}`} className="btn-text-link">
-                        View
+                        {t('engagement.list.view')}
                       </Link>
                       {canEditEngagements ? (
                         <>
                           <Link to={`/engagements/${eng.id}/edit`} className="btn-text-link">
-                            Edit
+                            {t('engagement.list.edit')}
                           </Link>
                           <button
                             type="button"
@@ -110,7 +108,7 @@ export function EngagementsListPage(): JSX.Element {
                             onClick={() => onDelete(eng)}
                             disabled={deleteMutation.isPending}
                           >
-                            Delete
+                            {t('engagement.list.delete')}
                           </button>
                         </>
                       ) : null}