feat: implement core-i18n package with decentralized namespace support and integrate into landing and web apps

apps/landing/src/app.tsx

@@ -1,6 +1,7 @@
 import { ThemeProvider } from '@repo/ui/provider';
 import { Button } from '@repo/ui/components';
 import LandingSample from './features/public-content/presentation/LandingSample';
+import I18nLandingSample from './presentation/I18nLandingSample';
 
 export default function App() {
   return (
@@ -36,6 +37,7 @@ export default function App() {
       <h1 className="text-2xl font-bold mb-4">Enterprise Web App</h1>
       <LandingSample />
       </div>
+      <I18nLandingSample />
     </div>
     </ThemeProvider>
   );