Avoid Pydantic serializer warnings

[Mini256]

/usr/local/lib/python3.11/site-packages/pydantic/_internal/_std_types_schema.py:291: UserWarning: Pydantic serializer warnings:
  Expected `enum` but got `int` - serialized value may not be as expected
  Expected `enum` but got `int` - serialized value may not be as expected
  Expected `enum` but got `int` - serialized value may not be as expected
  Expected `enum` but got `int` - serialized value may not be as expected
  Expected `enum` but got `int` - serialized value may not be as expected
  Expected `enum` but got `int` - serialized value may not be as expected
  Expected `enum` but got `int` - serialized value may not be as expected
  Expected `enum` but got `int` - serialized value may not be as expected
  v = handler(item, index)

[sszgwdk]

Which interface call will trigger this warning?

[sszgwdk]

The root of this issue lies in the mismatch between how SQLAlchemy and Pydantic handle enum values:

1. Pydantic expects to work with the ChatVisibility enum itself.
2. SQLAlchemy stores the enum as an integer (SmallInteger) in the database.
3. When fetching values from the database, SQLAlchemy provides raw integers (0 or 1), which leads to warnings during serialization because Pydantic requires the ChatVisibility enum type.