Adds a Ukrainian argument structure gallery example and supporting core fixes

[pkuchmiichuk]

Description

Adds a Ukrainian argument structure example to the gallery, plus the five bead/ core changes that building it required.

Gallery (gallery/ukr/argument_structure/)

An end-to-end 2AFC acceptability pipeline for Ukrainian verb argument structure, following the structure of gallery/eng/ and gallery/kor/ (korean branch): a Makefile, a local config.yaml, and numbered pipeline stages covering lexicon generation, template generation, template filling, 2AFC pair construction, list partitioning, and jsPsych/JATOS deployment.

Ukrainian specifics worth noting:

• Lexicons are built from VESUM Unimorph partition rather than standard UniMorph, via a UniMorphAdapter subclass in utils/vesum_adapter.py.
• Pairs contrast morphological case, since Ukrainian argument structure is case-marked. Case forms are filtered to unambiguous ones.
• Verb selection is frequency-based, driven by a committed wordfreq-derived table (resources/verb_frequencies.csv). build_frequencies.py regenerates it, but is meant to be run rarely so that the pipeline does not depend on wordfreq at run time.
• Scoring uses a causal LM for final scoring.

Core changes to bead/

Change	Files
ListConstraint subclasses now default constraint_type to their own discriminator value, so constraints no longer have to restate it at construction.	bead/lists/constraints.py
ListPartitioner warns once per expression when a constraint property expression cannot be evaluated, and once per type when a constraint type is not enforced during assignment. Previously a misconfigured constraint scored zero every iteration and was silently ignored.	bead/lists/partitioner.py
Causal LMs load in the checkpoint's own dtype by default (dtype="auto"), and the requested dtype is passed from LanguageModelScorer through to the adapter. Loading a half-precision checkpoint as float32 doubled its memory.	bead/items/adapters/huggingface.py, bead/items/scoring.py
UniMorphAdapter gained an overridable _load_dataset hook so a subclass can read a non-standard file layout.	bead/resources/adapters/unimorph.py

All four core changes are backward compatible. The new parameters are keyword arguments with defaults preserving existing behavior, and the constraint defaults only add a value where one previously had to be supplied.

Type of Change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
• Documentation update
• Refactoring (no functional changes)
• Tests (adding or updating tests)

Checklist

• I have read the CONTRIBUTING guidelines
• My code follows the project's style guidelines
• I have run uv run ruff check . and uv run ruff format .
• I have run uv run pyright with no errors
• I have added tests that prove my fix/feature works
• All tests pass (uv run pytest tests/)
• I have updated documentation as needed

Testing

Six test files cover the core changes:

Test file	Covers
tests/lists/test_constraints.py	Each constraint type constructs without an explicit constraint_type, and the discriminator still round-trips.
tests/lists/test_partitioner.py	The unresolved-expression warning fires once per expression.
tests/lists/test_partitioner_batch.py	The unenforced-type warning fires once per constraint type.
tests/items/adapters/test_huggingface.py	The adapter forwards dtype to from_pretrained and defaults to "auto".
tests/items/test_scoring.py	LanguageModelScorer passes its dtype through to the adapter.
tests/resources/adapters/test_unimorph.py	A subclass overriding _load_dataset is used in place of the module-level loader.

Note on gallery test coverage: gallery/ is excluded from ruff, pyright, and testpaths, so the Ukrainian pipeline scripts are not covered by CI, matching how gallery/eng/ and gallery/kor/ (korean branch) are currently treated.

[aaronstevenwhite]

Can you pull the core changes into a separate PR from the gallery addition and target the core changes at main but the gallery addition at ukrainian?

[pkuchmiichuk]

Split into two as requested: core changes target main in #11 , Ukrainian gallery targets ukrainian in #12 .