feat(vision-metrics): split vqa

[davidberenstein1957]

Summary

Splits vqa into its own stacked PR, adds VQAMetric, and wires GenAI Bench benchmark entry with focused VQA coverage.

Stack Position

• Base: PR feat(text-metrics): split oneig_reasoning #648 (feat/vlm-pr-3d-oneig-reasoning)
• Next: PR feat(vision-metrics): split vie_score #650 (feat/vlm-pr-4b-vie-score)
• Final integration: PR feat(e2e-tests): stacked e2e after split metrics #641 (feat/vlm-pr-5-e2e-tests)
• Canonical umbrella reference: PR feat(evaluation): add VLMMetrics #545 (feat/metrics-vlm-support)

Files

• src/pruna/evaluation/metrics/metric_vqa.py
• src/pruna/evaluation/benchmarks.py
• tests/evaluation/test_vision_metrics.py

Test Plan

uv run pytest tests/evaluation/test_vision_metrics.py -k vqa

Review Focus

• Yes-probability scoring
• GenAI Bench mapping

Review Flow (Order)

Review the stack in this exact order:

1. feat(vendor): add LLM2Vec embedding model #637 vendor
2. feat(infrastructure): add VLM base classes and utilities #638 infrastructure
3. feat(text-metrics): split qa_accuracy #645 qa_accuracy
4. feat(text-metrics): split oneig_alignment #646 oneig_alignment
5. feat(text-metrics): split text_score pair #647 text_score pair
6. feat(text-metrics): split oneig_reasoning #648 oneig_reasoning
7. feat(vision-metrics): split vqa #649 vqa
8. feat(vision-metrics): split vie_score #650 vie_score
9. feat(vision-metrics): split img_edit_score #651 img_edit_score
10. feat(e2e-tests): stacked e2e after split metrics #641 e2e tests

This PR in the flow (7/10)

• Review after PR feat(text-metrics): split oneig_reasoning #648.
• Next PR to review: feat(vision-metrics): split vie_score #650.
• Confirm this PR's tests and scope before continuing.