Complete test-driven development implementation:
- Profile model with full CRUD API (13 tests, django-filter integration)
- WallSection model with height calculations (11 tests, ice/crew validation)
- Django REST Framework serializers and viewsets with comprehensive test coverage
- Full type safety with django-stubs==5.2.6 and djangorestframework-stubs==3.16.4
- Fixed all 61 mypy errors: added type parameters to ModelSerializer[T] and ModelViewSet[T]
- Updated test fixtures with proper APIClient typing (was object)
- Upgraded factory-boy==3.3.3 for native type annotations
- Removed legacy mypy config from other projects
- 24 tests passing, 96% coverage, 0 mypy errors
