fix(chat): 修复 realtime 同步下 Name2Id 映射缺失

- 将 Name2Id 从随新消息顺带补写调整为按 live WCDB 整表同步\n- 修复输出库中 real_sender_id 无法稳定反查 sender_username 的问题\n- 消除必须删除当前项目数据并重新加载后 Name2Id 才能补全的问题\n- 增加 Name2Id 自愈同步回归测试，覆盖无新消息时的修复场景

tests/test_chat_realtime_name2id_sync.py

@@ -0,0 +1,117 @@
+import hashlib
+import sqlite3
+import sys
+import threading
+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"))
+
+from wechat_decrypt_tool.routers import chat as chat_router
+
+
+class _DummyConn:
+    def __init__(self) -> None:
+        self.handle = 1
+        self.lock = threading.Lock()
+
+
+class TestChatRealtimeName2IdSync(unittest.TestCase):
+    def test_sync_repairs_name2id_even_without_new_messages(self):
+        with TemporaryDirectory() as td:
+            account_dir = Path(td) / "acc"
+            account_dir.mkdir(parents=True, exist_ok=True)
+
+            username = "wxid_friend"
+            table_name = f"Msg_{hashlib.md5(username.encode('utf-8')).hexdigest()}"
+            msg_db_path = account_dir / "message_0.db"
+
+            conn = sqlite3.connect(str(msg_db_path))
+            try:
+                conn.execute("CREATE TABLE Name2Id (user_name TEXT, is_session INTEGER DEFAULT 1)")
+                conn.execute(
+                    """
+                    CREATE TABLE "{table_name}" (
+                        local_id INTEGER PRIMARY KEY,
+                        server_id INTEGER,
+                        local_type INTEGER,
+                        sort_seq INTEGER,
+                        real_sender_id INTEGER,
+                        create_time INTEGER,
+                        message_content TEXT,
+                        compress_content BLOB,
+                        packed_info_data BLOB
+                    )
+                    """.format(table_name=table_name)
+                )
+                conn.execute("INSERT INTO Name2Id(rowid, user_name, is_session) VALUES (1, ?, 1)", ("acc",))
+                conn.execute("INSERT INTO Name2Id(rowid, user_name, is_session) VALUES (2, ?, 1)", ("wxid_old",))
+                conn.execute("INSERT INTO Name2Id(rowid, user_name, is_session) VALUES (5, ?, 1)", ("wxid_gap_tail",))
+                conn.execute(
+                    f'INSERT INTO "{table_name}" '
+                    "(local_id, server_id, local_type, sort_seq, real_sender_id, create_time, message_content, compress_content, packed_info_data) "
+                    "VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)",
+                    (10, 10010, 1, 10, 3, 1710000010, "hello", None, None),
+                )
+                conn.commit()
+            finally:
+                conn.close()
+
+            live_rows = [
+                {"rowid": 1, "user_name": "acc", "is_session": 1},
+                {"rowid": 2, "user_name": "wxid_old", "is_session": 1},
+                {"rowid": 3, "user_name": "wxid_missing_a", "is_session": 1},
+                {"rowid": 4, "user_name": "wxid_missing_b", "is_session": 1},
+                {"rowid": 5, "user_name": "wxid_gap_tail", "is_session": 1},
+            ]
+
+            def _fake_exec_query(_handle, *, kind, path, sql):
+                self.assertEqual(kind, "message")
+                self.assertTrue(str(path).endswith("message_0.db"))
+                if "COUNT(1)" in sql:
+                    return [{"c": len(live_rows), "mx": 5}]
+                if "ORDER BY rowid ASC" in sql:
+                    return list(live_rows)
+                raise AssertionError(f"Unexpected SQL: {sql}")
+
+            with (
+                patch.object(chat_router, "_resolve_db_storage_message_paths", return_value=(Path(td) / "live_message_0.db", Path(td) / "message_resource.db")),
+                patch.object(chat_router, "_wcdb_exec_query", side_effect=_fake_exec_query),
+                patch.object(chat_router, "_wcdb_get_messages", return_value=[]),
+            ):
+                result = chat_router._sync_chat_realtime_messages_for_table(
+                    account_dir=account_dir,
+                    rt_conn=_DummyConn(),
+                    username=username,
+                    msg_db_path=msg_db_path,
+                    table_name=table_name,
+                    max_scan=50,
+                    backfill_limit=0,
+                )
+
+            self.assertEqual(result.get("inserted"), 0)
+
+            conn = sqlite3.connect(str(msg_db_path))
+            try:
+                rows = conn.execute("SELECT rowid, user_name FROM Name2Id ORDER BY rowid ASC").fetchall()
+            finally:
+                conn.close()
+
+            self.assertEqual(
+                rows,
+                [
+                    (1, "acc"),
+                    (2, "wxid_old"),
+                    (3, "wxid_missing_a"),
+                    (4, "wxid_missing_b"),
+                    (5, "wxid_gap_tail"),
+                ],
+            )
+
+
+if __name__ == "__main__":
+    unittest.main()