[Benchmark] Upgrade OmniDocBench to v1.5 - #1640

Summary

• make the pinned 1,355-page OmniDocBench v1.5 TSV the default OmniDocBench dataset
• retain the 981-page release as OmniDocBench_v1_0
• parse v1.0 JSON and the published v1.5 Python-literal annotation format safely
• pin both Hugging Face revisions and verify each download by MD5

Why

The v1.5 TSV already published in ouyanglinke/OmniDocBench_tsv cannot be evaluated by the current adapter: its answer column contains Python dictionary literals, so json.loads() rejects all 1,355 rows. The fallback here uses ast.literal_eval; it never executes annotation text.

Fixes #1456.

Validation

• downloaded the pinned 1,506,235,920-byte v1.5 TSV; MD5: 995f1af5b4e24ad0a6417cbff708b3fc
• parsed all 1,355 contiguous rows and checked page_info, layout_dets, and extra schemas
• decoded and loaded rows 0, 677, and 1,354 (JPEG/JPEG/PNG)
• exercised both end-to-end and table evaluator loading against a real v1.5 row: load_success=1, load_fail=0
• perfect real-table smoke prediction: TEDS 1.0 and structure-only TEDS 1.0
• 5 focused unit tests pass, including rejection of executable expressions
• py_compile, git diff --check, and all configured pre-commit hooks pass

Implementation and validation were performed with OpenAI Codex assistance; I reviewed the resulting code, dataset provenance, hashes, and executed checks.