fix(tkeg): JWT 파싱 시 한글 이름 깨짐 수정 (UTF-8 디코딩)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

tkeg/web/src/App.jsx

@@ -23,7 +23,12 @@ function parseJwt(token) {
   try {
     const base64Url = token.split('.')[1];
     const base64 = base64Url.replace(/-/g, '+').replace(/_/g, '/');
-    return JSON.parse(atob(base64));
+    const jsonPayload = decodeURIComponent(
+      atob(base64).split('').map(c =>
+        '%' + ('00' + c.charCodeAt(0).toString(16)).slice(-2)
+      ).join('')
+    );
+    return JSON.parse(jsonPayload);
   } catch { return null; }
 }