feat: add Korean-English localization and light theme

Localize studio, curriculum, visualization and loading interfaces. Add persistent language and theme settings, refine module loading states, and normalize remote shell locales.

src/renderer/public/splash.html

@@ -78,11 +78,23 @@
     document.getElementById('splash-image').src = './assets/splash.png'
 
     const el = document.getElementById('loading-text')
+    const translations = {
+      '학습 환경 준비 중...': 'Preparing your learning environment...',
+      '로그인 세션 확인 중...': 'Checking your session...',
+      '강좌 정보 불러오는 중...': 'Loading courses...',
+      '커리큘럼 및 플랫폼 정보 가져오는 중...': 'Loading curriculum and platforms...'
+    }
+    let language = 'ko'
+    try {
+      language = localStorage.getItem('autonomy-studio.lms.language') === 'en' ? 'en' : 'ko'
+    } catch {}
+    document.documentElement.lang = language
     window.setSplashStatus = (message) => {
       if (typeof message === 'string' && message.trim()) {
-        el.textContent = message
+        el.textContent = language === 'en' ? (translations[message] ?? message) : message
       }
     }
+    window.setSplashStatus(el.textContent)
   </script>
 </body>
 </html>