feat(config): 支持从host_config.yaml加载配置

当host_config.yaml存在时优先使用该文件，否则回退到keyring.yaml

config.py

@@ -3,10 +3,12 @@ from pathlib import Path
 from typing import Any, Dict, List, Optional
 
 _CONFIG_PATH = Path(__file__).parent / "keyring.yaml"
+_HOST_CONFIG_PATH = Path(__file__).parent / "host_config.yaml"
 
 
 def _load() -> dict[str, Any]:
-    with open(_CONFIG_PATH, "r", encoding="utf-8") as f:
+    config_path = _HOST_CONFIG_PATH if _HOST_CONFIG_PATH.exists() else _CONFIG_PATH
+    with open(config_path, "r", encoding="utf-8") as f:
         return yaml.safe_load(f) or {}