fix: standardize UTC timestamp handling

templates/admin.html

@@ -72,7 +72,7 @@
         {% for user in password_reset_users %}
         <tr class="hover:bg-slate-50">
           <td class="px-4 py-3 font-semibold">{{ user.username }}</td>
-          <td class="px-4 py-3 text-textSub">{{ user.created_at.strftime('%Y-%m-%d %H:%M:%S') if user.created_at else '-' }}</td>
+          <td class="px-4 py-3 text-textSub">{{ format_datetime(user.created_at) }}</td>
           <td class="px-4 py-3">
             <form method="post" action="{{ url_for('main.create_password_reset_link', user_id=user.id) }}" data-reset-link-form class="inline-flex">
               <input type="hidden" name="csrf_token" value="{{ csrf_token() }}">
@@ -117,7 +117,7 @@
         <tr class="hover:bg-slate-50">
           <td class="px-5 py-4 font-semibold">{{ record.user.username }}</td>
           <td class="max-w-[420px] truncate px-5 py-4">{{ record.original_filename }}</td>
-          <td class="px-5 py-4 text-textSub">{{ record.upload_time.strftime('%Y-%m-%d %H:%M:%S') }}</td>
+          <td class="px-5 py-4 text-textSub">{{ format_datetime(record.upload_time) }}</td>
           <td class="px-5 py-4">
             <div class="flex flex-wrap gap-3">
               <a class="font-bold text-primary" href="{{ url_for('main.download_file', record_id=record.id, file_type='original') }}">原始文件</a>

templates/history.html

@@ -31,7 +31,7 @@
       <div class="min-w-0 overflow-hidden">
         <div class="truncate text-sm font-bold">{{ record.original_filename }}</div>
         <div class="mt-1 flex flex-wrap items-center gap-2 text-xs text-textSub">
-          <span>{{ record.upload_time.strftime('%Y-%m-%d %H:%M:%S') }}</span>
+          <span>{{ format_datetime(record.upload_time) }}</span>
           <span class="hidden sm:inline">·</span>
           <span>记录 #{{ record.id }}</span>
         </div>