added runtime check for this

tests/unit_tests/repository_tests/test_query_filter_builder.py

@@ -1,6 +1,7 @@
 import pytest
 import sqlalchemy as sa
 
+from mealie.db.models._model_base import PrivateColumn
 from mealie.db.models.recipe.recipe import RecipeModel
 from mealie.db.models.users.users import LongLiveToken, User
 from mealie.services.query_filter.builder import (
@@ -87,6 +88,12 @@ def test_query_filter_builder_json_uses_raw_value():
 # ---------------------------------------------------------------------------
 
 
+def test_private_column_rejects_list_type():
+    """PrivateColumn[list[X]] must raise TypeError at definition time to prevent misuse on relationships."""
+    with pytest.raises(TypeError, match="relationship"):
+        PrivateColumn[list[User]]
+
+
 def test_private_field_user_password_raises():
     """Filtering on User.password (PrivateColumn) should raise ValueError."""
     with pytest.raises(ValueError, match="private field"):