refactor(config): retire RuntimeSettingsCompat host usage

tests/test_downloader_path_mapping.py

@@ -272,13 +272,6 @@ def _load_transmission_module():
         def get(self, *_args, **_kwargs):
             return None
 
-    class _RuntimeSettingsCompat:
-        """隔离测试用动态配置代理，保持生产模块的兼容读取语义。"""
-
-        def __getattr__(self, key):
-            """从测试提供的旧 Settings 桩读取配置项。"""
-            return getattr(config_module.settings, key)
-
     transmission_client_module.Transmission = object
     cache_module.FileCache = _FileCache
     schema_transfer_module.TransferTorrent = _TransferTorrent
@@ -294,7 +287,9 @@ def _load_transmission_module():
         "DownloaderType", {"Transmission": "Transmission"}
     )
     config_module.settings = SimpleNamespace(TORRENT_TAG="moviepilot-tag")
-    runtime_settings_module.RuntimeSettingsCompat = _RuntimeSettingsCompat
+    runtime_settings_module.get_runtime_setting = lambda key, default=None: getattr(
+        config_module.settings, key, default
+    )
     metainfo_module.MetaInfo = _MetaInfo
     log_module.logger = _Logger()
     modules_module._ModuleBase = _ModuleBase