improvement(chat): 完善会话置顶与消息卡片解析展示

- 后端：会话列表支持置顶识别(isTop)并按置顶优先排序

- 后端：修正群聊 XML 发送者提取，避免 refermsg 嵌套误识别

- 后端：完善转账状态后处理与视频缩略图 MD5 回填(packed_info_data)

- 后端：补充 quoteThumbUrl/linkType/linkStyle 字段链路

- 前端：新增置顶会话背景态、引用链接缩略图预览与 LinkCard cover 样式

- 测试：新增转账、置顶、引用解析与视频缩略图相关回归用例

tests/test_transfer_status_text.py

@@ -0,0 +1,63 @@
+import sys
+import unittest
+from pathlib import Path
+
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT / "src"))
+
+from wechat_decrypt_tool.chat_helpers import _infer_transfer_status_text
+
+
+class TestTransferStatusText(unittest.TestCase):
+    def test_paysubtype_3_sent_side(self):
+        status = _infer_transfer_status_text(
+            is_sent=True,
+            paysubtype="3",
+            receivestatus="",
+            sendertitle="",
+            receivertitle="",
+            senderdes="",
+            receiverdes="",
+        )
+        self.assertEqual(status, "已被接收")
+
+    def test_paysubtype_3_received_side(self):
+        status = _infer_transfer_status_text(
+            is_sent=False,
+            paysubtype="3",
+            receivestatus="",
+            sendertitle="",
+            receivertitle="",
+            senderdes="",
+            receiverdes="",
+        )
+        self.assertEqual(status, "已收款")
+
+    def test_receivestatus_1_sent_side(self):
+        status = _infer_transfer_status_text(
+            is_sent=True,
+            paysubtype="1",
+            receivestatus="1",
+            sendertitle="",
+            receivertitle="",
+            senderdes="",
+            receiverdes="",
+        )
+        self.assertEqual(status, "已被接收")
+
+    def test_receivestatus_1_received_side(self):
+        status = _infer_transfer_status_text(
+            is_sent=False,
+            paysubtype="1",
+            receivestatus="1",
+            sendertitle="",
+            receivertitle="",
+            senderdes="",
+            receiverdes="",
+        )
+        self.assertEqual(status, "已收款")
+
+
+if __name__ == "__main__":
+    unittest.main()