fix(time): use UTC methods for operation history display

The database stores time in UTC format, and the UI should display UTC
time without timezone conversion. Use getUTCXxx() methods instead of
getHours() to avoid adding 8-hour timezone offset.

Also extract common datetime formatting logic to reduce code duplication.

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

src/renderer/src/components/ExtractorOperationHistoryModal.tsx

@@ -53,13 +53,20 @@ const statusIcons: Record<string, React.ReactNode> = {
 
 const formatDateTime = (dateStr: string) => {
   const date = new Date(dateStr)
-  return date.toLocaleString('zh-CN', {
-    year: 'numeric',
-    month: '2-digit',
-    day: '2-digit',
-    hour: '2-digit',
-    minute: '2-digit'
-  })
+
+  // Check if the date is valid
+  if (isNaN(date.getTime())) {
+    return dateStr // Return original if invalid
+  }
+
+  // Use UTC methods to display the time as stored in database (without timezone conversion)
+  const year = date.getUTCFullYear()
+  const month = String(date.getUTCMonth() + 1).padStart(2, '0')
+  const day = String(date.getUTCDate()).padStart(2, '0')
+  const hours = String(date.getUTCHours()).padStart(2, '0')
+  const minutes = String(date.getUTCMinutes()).padStart(2, '0')
+
+  return `${year}-${month}-${day} ${hours}:${minutes}`
 }
 
 export const ExtractorOperationHistoryModal: React.FC<ExtractorOperationHistoryModalProps> = ({