fix: admin table i18n + emoji preservation in nav items

- Admin panel: table headers, data values, date locale-aware
- Settings/help nav: emojis added to locale values (🔍🔧🔄 etc.)
- auth.js: getLocale import, t() for all user-facing strings
- Added common.never + 6 admin column keys
- 746 locale keys per language

frontend/js/auth.js

@@ -2,7 +2,7 @@
 import { state } from './state.js';
 import { safeCreateIcons } from './utils.js';
 import { showToast, closeHeaderMenu } from './ui.js';
-import { t } from './i18n.js';
+import { t, getLocale } from './i18n.js';
 import { showWelcome } from './viewer.js';
 
 // ---------------------------------------------------------------------------
@@ -398,11 +398,13 @@ const AdminPanel = {
       container.innerHTML = '<p style="padding:16px;color:var(--text-muted);">Aucun utilisateur.</p>';
       return;
     }
-    let html = '<table class="admin-table"><thead><tr>' + "<th>Utilisateur</th><th>Rôle</th><th>Vaults</th><th>Statut</th><th>Dernière connexion</th><th>Actions</th>" + "</tr></thead><tbody>";
+    let html = '<table class="admin-table"><thead><tr>' +
+      '<th>' + t('admin.col_user') + '</th><th>' + t('admin.col_role') + '</th><th>' + t('admin.col_vaults') + '</th><th>' + t('admin.col_status') + '</th><th>' + t('admin.col_last_login') + '</th><th>' + t('admin.col_actions') + '</th>' +
+      '</tr></thead><tbody>';
     users.forEach((u) => {
-      const vaults = u.vaults.includes("*") ? "Toutes" : u.vaults.join(", ") || "Aucune";
+      const vaults = u.vaults.includes("*") ? t('common.all') : u.vaults.join(", ") || t('common.none');
       const status = u.active ? "✅" : "🔴";
-      const lastLogin = u.last_login ? new Date(u.last_login).toLocaleDateString("fr-FR", { day: "numeric", month: "short", year: "numeric", hour: "2-digit", minute: "2-digit" }) : "Jamais";
+      const lastLogin = u.last_login ? new Date(u.last_login).toLocaleDateString(getLocale() === 'fr' ? 'fr-FR' : 'en-US', { day: "numeric", month: "short", year: "numeric", hour: "2-digit", minute: "2-digit" }) : t('common.never');
       html +=
         "<tr>" +
         "<td><strong>" +
@@ -427,10 +429,10 @@ const AdminPanel = {
         '<td class="admin-actions">' +
         '<button class="admin-action-btn" data-action="edit" data-username="' +
         u.username +
-        '" title="Modifier">✏️</button>' +
+        '" title="' + t('common.edit') + '">✏️</button>' +
         '<button class="admin-action-btn danger" data-action="delete" data-username="' +
         u.username +
-        '" title="Supprimer">🗑️</button>' +
+        '" title="' + t('common.delete') + '">🗑️</button>' +
         "</td></tr>";
     });
     html += "</tbody></table>";