refactor(admin): replace static dashboard stats with dynamic widget registry

src/features/auth/dashboard.server.js

@@ -0,0 +1,22 @@
+/**
+ * Auth Feature — Contribution serveur au tableau de bord
+ *
+ * Ce module s'auto-enregistre auprès du registre admin en side effect.
+ * Dépendance correcte : auth → admin (feature → core).
+ */
+
+import { registerServerWidget } from '../admin/dashboard/registry.js';
+import { query } from '@zen/core/database';
+import { fail } from '@zen/core/shared/logger';
+
+async function getDashboardData() {
+  try {
+    const result = await query(`SELECT COUNT(*) as count FROM zen_auth_users`);
+    return { totalUsers: parseInt(result.rows[0].count) || 0 };
+  } catch (error) {
+    fail(`Auth dashboard data error: ${error.message}`);
+    return { totalUsers: 0 };
+  }
+}
+
+registerServerWidget('auth', getDashboardData);