feat: persist system settings and refine admin layouts

backend/app/models/__init__.py

@@ -2,14 +2,18 @@ from app.models.user import User
 from app.models.gpu_cluster import GPUCluster
 from app.models.task import CollectionTask
 from app.models.datasource import DataSource
+from app.models.datasource_config import DataSourceConfig
 from app.models.alert import Alert, AlertSeverity, AlertStatus
+from app.models.system_setting import SystemSetting
 
 __all__ = [
     "User",
     "GPUCluster",
     "CollectionTask",
     "DataSource",
+    "DataSourceConfig",
+    "SystemSetting",
     "Alert",
     "AlertSeverity",
     "AlertStatus",
-]
+]