fix(tkuser): 연차설정 저장 시 settings 객체→배열 변환 누락 수정

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

user-management/web/static/js/tkuser-vacation-settings.js

@@ -150,7 +150,8 @@ async function saveVacationSettings() {
     if (!Object.keys(changes).length) { showToast('변경된 설정이 없습니다.', 'error'); return; }
 
     try {
-        await api('/vacation-settings', { method: 'PUT', body: JSON.stringify({ settings: changes }) });
+        const settingsArr = Object.entries(changes).map(([setting_key, setting_value]) => ({ setting_key, setting_value: String(setting_value) }));
+        await api('/vacation-settings', { method: 'PUT', body: JSON.stringify({ settings: settingsArr }) });
         showToast('설정이 저장되었습니다.');
         vacSettingsLoaded = false;
         await loadVacationSettingsTab();