[BENCHMARK] Add HPS (Human Preference Score) benchmark

[davidberenstein1957]

Description

Add HPS benchmark for text-to-image evaluation. Uses zhwang/HPDv2 dataset with 4 categories.

Details

• Dataset: zhwang/HPDv2 (benchmark subfolder contains JSON files)
• Categories: anime, concept-art, paintings, photo
• Collate: prompt_with_auxiliaries_collate

Implementation

• Add setup_hps_dataset in src/pruna/data/datasets/prompt.py
• Register in base_datasets in src/pruna/data/__init__.py
• Add BenchmarkInfo entry with metrics: ["hps"]
• Add test in tests/data/test_datamodule.py

Acceptance Criteria

• PrunaDataModule.from_string("HPS") works
• Category filter: PrunaDataModule.from_string("HPS", category="anime")
• Auxiliaries include category field
• Test passes