完善会话草稿恢复与附件保留，统一人工服务时区

tests/test_dev_integration.py

@@ -1,6 +1,6 @@
 """Remote dev behavior on the modular backend and the light workspace."""
 
-from datetime import datetime
+from datetime import datetime, timezone
 import io
 from pathlib import Path
 import tempfile
@@ -50,6 +50,19 @@ class DevIntegrationTests(unittest.TestCase):
         self.assertEqual(self.client.post('/api/ticket', json={'content': '周末留言'}).json, {'ok': True})
         self.assertEqual(self.client.get('/api/tickets').json[0]['content'], '周末留言')
 
+    def test_service_hours_use_china_time_even_when_the_host_clock_is_utc(self):
+        cid = self.client.post('/api/new_chat').json['id']
+        for utc_hour, expected in ((0, True),(13, True),(14, False),(23, False)):
+            instant = datetime(2026,10,31,utc_hour,tzinfo=timezone.utc)
+            class HostUtcClock(datetime):
+                @classmethod
+                def now(cls, tz=None):
+                    return instant.astimezone(tz) if tz else instant.replace(tzinfo=None)
+            with self.subTest(utc_hour=utc_hour), patch('logistics_chat.human_service.datetime', HostUtcClock):
+                result = self.client.post('/api/visitor/human/request',json={'conv_id':cid}).json
+                self.assertEqual(result['ok'],expected)
+                if not expected: self.assertTrue(result['closed'])
+
     def test_transfer_returns_to_queue_preserves_messages_and_note(self):
         sid = self.session()
         self.client.post('/api/human/accept', json={'sid': sid})