[Aschenbath]

Fixes #228.

Converter (formerly GenConverter) accepted a dict_factory argument, but the generated unstructure hooks always built a plain dict literal, so Converter(dict_factory=OrderedDict).unstructure(obj) returned plain dicts. The interpreted BaseConverter.unstructure_attrs_asdict path did honor the factory.

make_dict_unstructure_fn_from_attrs now checks the converter's factory: with the default dict factory the generated code is unchanged (a dict literal); with any other factory the generated function builds the result through the factory (res = __c_dict_factory() followed by item assignments, mirroring unstructure_attrs_asdict), including for fields omitted via omit_if_default. Nested attrs classes generated from the same converter use the factory too.

Tests:

• Added test_dict_factory_used_by_generated_hooks to tests/test_gen_dict.py, covering a converter-level factory for nested classes, an explicitly generated hook, and combination with omit_if_default=True.
• Regression runs: tests/test_gen_dict.py, tests/test_dicts.py, tests/test_baseconverter.py (132 passed); tests/test_preconf.py, tests/test_typeddicts.py, tests/test_structure.py, tests/test_unstructure.py, tests/test_unstructure_collections.py, tests/test_generics.py, tests/test_copy.py (211 passed, 20 skipped; 2 pre-existing test_tomllib_converter* failures also occur on unmodified upstream main in this environment).
• ruff check and ruff format --check on the changed files: pass.

A changelog entry is included in HISTORY.md.

[Aschenbath]

Closing this one myself: I opened too many PRs here in a short time, which isn't fair to your review queue — sorry about that. I'm leaving #827 and #822 open. If this fix is something you'd want, I'm happy to reopen or rebase it later.