feat(admin): add email change flow with confirmation for users

- add `ConfirmEmailChangePage.client.js` for email change token confirmation
- add `emailChange.js` core utility to generate and verify email change tokens
- add `EmailChangeConfirmEmail.js` and `EmailChangeNotifyEmail.js` email templates
- update `UserEditModal` to handle email changes with password verification for self-edits
- update `ProfilePage` to support email change initiation
- update `UsersPage` to pass `currentUserId` to `UserEditModal`
- add email change API endpoints in `auth/api.js` and `auth/email.js`
- register `ConfirmEmailChangePage` in `AdminPage.client.js`

src/features/admin/pages/UsersPage.client.js

@@ -8,7 +8,7 @@ import { useToast } from '@zen/core/toast';
 import AdminHeader from '../components/AdminHeader.js';
 import UserEditModal from '../components/UserEditModal.client.js';
 
-const UsersPageClient = () => {
+const UsersPageClient = ({ currentUserId }) => {
     const toast = useToast();
     const [users, setUsers] = useState([]);
     const [loading, setLoading] = useState(true);
@@ -164,6 +164,7 @@ const UsersPageClient = () => {
 
             <UserEditModal
                 userId={editingUserId}
+                currentUserId={currentUserId}
                 isOpen={!!editingUserId}
                 onClose={() => setEditingUserId(null)}
                 onSaved={fetchUsers}
@@ -172,10 +173,10 @@ const UsersPageClient = () => {
     );
 };
 
-const UsersPage = () => (
+const UsersPage = ({ user }) => (
     <div className="flex flex-col gap-4 sm:gap-6 lg:gap-8">
         <AdminHeader title="Utilisateurs" description="Gérez les comptes utilisateurs" />
-        <UsersPageClient />
+        <UsersPageClient currentUserId={user?.id} />
     </div>
 );