fix: 修复广西政采网公告时间时区错误

fromtimestamp() 在 UTC 服务器上会少 8 小时，改为明确指定 Asia/Shanghai 时区解析。

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

app/crawler/parsers.py

@@ -2,6 +2,9 @@ import hashlib
 from datetime import datetime
 from typing import Any
 from urllib.parse import urljoin
+from zoneinfo import ZoneInfo
+
+_TZ = ZoneInfo("Asia/Shanghai")
 
 from bs4 import BeautifulSoup
 
@@ -30,7 +33,7 @@ def parse_gxgp_api_response(
         if not timestamp:
             continue
         try:
-            publish_date = datetime.fromtimestamp(int(timestamp) / 1000)
+            publish_date = datetime.fromtimestamp(int(timestamp) / 1000, tz=_TZ).replace(tzinfo=None)
         except (ValueError, TypeError):
             continue