fix(chat): 修复 list_chat_messages 中 re 作用域遮蔽

- 移除函数内局部 import re，避免遮蔽模块级 re。

- 保持 emojiUrl 处理后续正则逻辑可稳定执行。

- 新增回归测试，覆盖模板解析路径，防止同类作用域问题复发。

src/wechat_decrypt_tool/routers/chat.py

@@ -5494,8 +5494,6 @@ def list_chat_messages(
 
                     if existing_local:
                         try:
-                            import re
-
                             cur = str(m.get("emojiUrl") or "")
                             if cur and re.match(r"^https?://", cur, flags=re.I) and ("/api/chat/media/emoji" not in cur):
                                 m["emojiRemoteUrl"] = cur

tests/test_chat_list_messages_re_scope.py

@@ -0,0 +1,67 @@
+import sys
+import unittest
+from pathlib import Path
+from tempfile import TemporaryDirectory
+from unittest.mock import patch
+
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT / "src"))
+
+
+class TestChatListMessagesReScope(unittest.TestCase):
+    def test_list_chat_messages_does_not_shadow_re(self):
+        from starlette.requests import Request
+
+        import wechat_decrypt_tool.routers.chat as chat
+
+        class _Sentinel(Exception):
+            pass
+
+        def fake_collect_chat_messages(**_kwargs):
+            merged = [
+                {
+                    "id": "1",
+                    "sortSeq": 0,
+                    "createTime": 1,
+                    "localId": 1,
+                    "type": 266287972401,
+                    "_rawText": "<msg><template>${wxid_abc}</template></msg>",
+                    "renderType": "appmsg",
+                }
+            ]
+            return merged, False, [], [], set()
+
+        scope = {
+            "type": "http",
+            "method": "GET",
+            "path": "/api/chat/messages",
+            "raw_path": b"/api/chat/messages",
+            "query_string": b"",
+            "headers": [],
+            "client": ("testclient", 12345),
+            "server": ("testserver", 80),
+            "scheme": "http",
+        }
+        request = Request(scope)
+
+        with TemporaryDirectory() as td:
+            account_dir = Path(td) / "acc"
+            account_dir.mkdir(parents=True, exist_ok=True)
+
+            sentinel = _Sentinel("stop-after-template-parse")
+
+            with patch.object(chat, "_resolve_account_dir", return_value=account_dir), patch.object(
+                chat, "_iter_message_db_paths", return_value=[account_dir / "msg_0.db"]
+            ), patch.object(chat, "_collect_chat_messages", side_effect=fake_collect_chat_messages), patch.object(
+                chat, "_postprocess_transfer_messages", lambda _merged: None
+            ), patch.object(chat, "_extract_xml_tag_text", return_value="${wxid_abc}"), patch.object(
+                chat, "_load_contact_rows", side_effect=sentinel
+            ):
+                with self.assertRaises(_Sentinel):
+                    chat.list_chat_messages(request=request, username="44372432598@chatroom", account="acc")
+
+
+if __name__ == "__main__":
+    unittest.main()
+