style(i18n): address code review - use optional chaining and stricter types

Co-authored-by: hotlong <50353452+hotlong@users.noreply.github.com>
Agent-Logs-Url: https://github.com/objectstack-ai/objectui/sessions/c9dec823-2a7f-43fa-a55e-6b357fefe3d5

Author: Copilot

apps/console/src/__tests__/LoadLanguage.test.tsx

@@ -13,7 +13,7 @@ import { loadLanguage } from '../loadLanguage';
 // Tests
 // ---------------------------------------------------------------------------
 describe('loadLanguage', () => {
-  const fetchSpy = vi.fn<(...args: any[]) => Promise<Response>>();
+  const fetchSpy = vi.fn<(...args: Parameters<typeof fetch>) => Promise<Response>>();
 
   beforeEach(() => {
     vi.stubGlobal('fetch', fetchSpy);

apps/console/src/loadLanguage.ts

@@ -15,7 +15,7 @@ export async function loadLanguage(lang: string): Promise<Record<string, unknown
     }
     const json = await res.json();
     // Unwrap the spec REST API envelope when present
-    if (json && typeof json === 'object' && json.data && json.data.translations && typeof json.data.translations === 'object') {
+    if (json?.data?.translations && typeof json.data.translations === 'object') {
       return json.data.translations as Record<string, unknown>;
     }
     // Fallback: mock server / local dev returns flat translation objects