fix(i18n): add time format translations to all 13 missing locales

Also translate server error message to English and remove stale
comment from calendar.js catch block.

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

public/locales/zh.json

@@ -607,6 +607,9 @@
     "dateFormatLabel": "首选日期格式",
     "dateFormatHint": "选择日期在应用中的显示方式。",
     "dateFormatSavedToast": "日期格式已保存。",
+    "timeFormatLabel": "时间格式",
+    "timeFormatHours": "小时",
+    "timeFormatSavedToast": "时间格式已保存。",
     "themeSystem": "跟随系统",
     "themeSysLabel": "使用系统设置",
     "themeLight": "浅色",