Add tests for default parameter paths in `affect_utils.py`

[lamurian]

User Story

As a developer, I want to add tests that call functions in src/python/affect_utils.py without optional parameters so that the default object creation logic is validated and overall code coverage is improved.

Description

affect_utils.py currently has 91% coverage. The missing 9% corresponds to code paths where default objects are created when optional parameters are None. Since existing tests always pass parameters explicitly, these fallback branches are not exercised. We need additional tests that omit optional arguments to trigger the default instantiations.

Proposed Flow

• Add tests for functions that rely on default parameter creation
• Cover InteractionConfig() instantiations (Lines 78, 104, 128, 156)
• Cover default object creation at Lines 247, 276, 282, 322, 346
• Ensure all new tests pass and integrate with coverage reporting

Reference

• Current coverage report for src/python/affect_utils.py
• InteractionConfig class used as a default configuration object

Notes:

• Keep test cases minimal but sufficient to exercise fallback logic.
• Validate that functions behave consistently whether parameters are provided explicitly or created by default.
• Ensure tests remain deterministic and avoid external dependencies.