- dataclass: 4 tests for basic model, fields, defaults, multiple tables
- sqlalchemy (legacy): 4 tests for basic model, columns, FK, multiple tables
- sqlalchemy_core: 5 tests (skipped - generator has known bugs)
- sqlmodel: 4 tests (skipped - requires Pydantic>=2.0, conflicts with table-meta)
- gino: 4 tests (skipped - requires SQLAlchemy<1.4, conflicts with SQLAlchemy>=2.0)

Note: Some tests are skipped due to dependency conflicts:
- sqlmodel requires pydantic>=2.0, but table-meta requires pydantic<2.0
- gino requires sqlalchemy<1.4, but we use sqlalchemy>=2.0
- sqlalchemy_core generator has bugs (missing column names, broken type sizes)

- Separate tox environments for different dependency requirements:
  - py39-py313: unit and functional tests
  - integration-sqlalchemy: pydantic v1, sqlalchemy v2
  - integration-gino: pydantic v1, sqlalchemy v1.3 (gino requirement)

- Separate CI jobs for each integration test group

- SQLModel integration tests disabled due to unresolvable conflict:
  - sqlmodel requires pydantic>=2.0
  - table-meta requires pydantic<2.0
  - Tests will be skipped until table-meta adds pydantic 2.x support

Integration tests now use pre-generated code fixtures instead of
calling create_models() at runtime. This allows SQLModel tests to
run in an isolated environment with pydantic>=2.0 without conflicts.

Tests verify that the generated code (as users would commit to their repos)
works correctly with the target library.

- Fix sqlalchemy_core generator: add column names to output
- Fix sqlalchemy_core generator: include type name with size
- Fix sqlalchemy_core generator: correct positional/keyword arg order for ForeignKey
- Convert gino tests to pre-generated code fixtures (no omymodels dependency)
- Update tox.ini and CI workflow for isolated gino tests
- Remove flawed parametrized converter test (py-models-parser limitations)
- Update functional test expected values for sqlalchemy_core