fix(data): read_db_daily 配置 vnpy database 路径（修端到端读取 gap）

Fix: read_db_daily 现在在调用 get_database() 前配置 vnpy SETTINGS，
指向 cfg.data_paths["vnpy_db"]（NAS quant_trading.db），修复端到端冒烟发现的读取 gap。

tests/data/test_datareader.py

@@ -1,7 +1,9 @@
 import pandas as pd
+from unittest.mock import patch, MagicMock
 from vnpy.trader.constant import Exchange, Interval
+from vnpy.trader.setting import SETTINGS
 from sanguo_data.config import DataConfig
-from sanguo_data.datareader import read_parquet_daily, guess_exchange
+from sanguo_data.datareader import read_parquet_daily, guess_exchange, read_db_daily
 
 def test_read_parquet_daily_returns_bardata(tmp_path):
     year_dir = tmp_path / "2026"
@@ -30,3 +32,23 @@ def test_guess_exchange_sh():
 
 def test_guess_exchange_sz():
     assert guess_exchange("000001").value == "SZSE"
+
+
+def test_read_db_daily_configures_vnpy_settings():
+    """Test that read_db_daily configures vnpy SETTINGS with correct database path."""
+    cfg = DataConfig(
+        data_paths={"vnpy_db": "/volume1/stock/sanguo_vnpy/data/quant_trading.db"},
+        data_sources={}, validation={}, performance={},
+    )
+
+    # Mock get_database to avoid actual database connection
+    mock_db = MagicMock()
+    mock_db.load_bar_data.return_value = []  # Return empty list to avoid data processing
+
+    with patch('sanguo_data.datareader.get_database', return_value=mock_db):
+        # Call read_db_daily
+        read_db_daily("600000", "2024-01-01", "2024-12-31", cfg)
+
+        # Assert that SETTINGS was configured correctly
+        assert SETTINGS["database.name"] == "sqlite", f"Expected database.name to be 'sqlite', got {SETTINGS.get('database.name')}"
+        assert SETTINGS["database.database"] == cfg.data_paths["vnpy_db"], f"Expected database.database to be {cfg.data_paths['vnpy_db']}, got {SETTINGS.get('database.database')}"