fix: bound SavedModel graph traversal

[mldangelo-oai]

Summary

• add pre-traversal budgets for SavedModel meta graphs, graph nodes, function count, and function-body nodes
• fail closed as inconclusive with savedmodel_graph_traversal_budget_exceeded when budgets are exceeded
• add oversized graph/function positives and benign at-budget negative coverage

Validation

• PYTHONPATH=/private/tmp/modelaudit-c140 PROMPTFOO_DISABLE_TELEMETRY=1 /Users/mdangelo/code/modelaudit/.venv/bin/pytest tests/scanners/test_tf_savedmodel_scanner.py -q: 65 passed
• ruff format --check modelaudit/scanners/tf_savedmodel_scanner.py tests/scanners/test_tf_savedmodel_scanner.py
• ruff check modelaudit/scanners/tf_savedmodel_scanner.py tests/scanners/test_tf_savedmodel_scanner.py
• mypy modelaudit/scanners/tf_savedmodel_scanner.py tests/scanners/test_tf_savedmodel_scanner.py
• git diff --check

[mldangelo-oai]

@codex review

[github-actions]

Workflow run and artifacts

Performance Benchmarks

Compared 12 shared benchmarks with a regression threshold of 15%.
Status: 0 regressions, 0 improved, 12 stable, 0 new, 0 missing.
Aggregate shared-benchmark median: 757.30ms -> 797.79ms (+5.3%).

Workload	Benchmark	Target	Size	Files	Baseline	Current	Change	Status
mixed-model-repository	tests/benchmarks/test_scan_benchmarks.py::test_scan_release_candidate_repository	release-candidate	547.3 KiB	32	291.46ms	313.68ms	+7.6%	stable
suspicious-pickle-intake	tests/benchmarks/test_scan_benchmarks.py::test_scan_suspicious_pickle_intake	suspicious-intake	183.8 KiB	4	98.08ms	104.50ms	+6.6%	stable
duplicate-heavy-registry	tests/benchmarks/test_scan_benchmarks.py::test_scan_duplicate_registry_snapshot	registry-snapshot	915.2 KiB	13	208.66ms	217.52ms	+4.2%	stable
chunked-upload-stream	tests/benchmarks/test_picklescan_benchmarks.py::test_picklescan_chunked_upload_stream	chunked_stream	278.2 KiB	1	23.14ms	24.09ms	+4.1%	stable
single-checkpoint-preflight	tests/benchmarks/test_scan_benchmarks.py::test_scan_single_checkpoint_before_load	single_checkpoint.pkl	183.0 KiB	1	38.64ms	40.16ms	+3.9%	stable
nested-payload-review	tests/benchmarks/test_picklescan_benchmarks.py::test_picklescan_nested_payload_review[nested_base64]	nested_base64	98 B	1	472.7us	481.1us	+1.8%	stable
direct-malicious-upload	tests/benchmarks/test_picklescan_benchmarks.py::test_picklescan_direct_malicious_upload	malicious_reduce	52 B	1	1.57ms	1.59ms	+1.2%	stable
warm-cache-rescan	tests/benchmarks/test_scan_benchmarks.py::test_scan_warm_cached_repository_rescan	release-candidate	547.3 KiB	32	72.28ms	72.88ms	+0.8%	stable
clean-training-checkpoint	tests/benchmarks/test_picklescan_benchmarks.py::test_picklescan_clean_training_checkpoint	safe_large	278.2 KiB	1	20.38ms	20.28ms	-0.5%	stable
nested-payload-review	tests/benchmarks/test_picklescan_benchmarks.py::test_picklescan_nested_payload_review[nested_raw]	nested_raw	78 B	1	472.1us	473.7us	+0.3%	stable
padded-multi-stream-upload	tests/benchmarks/test_picklescan_benchmarks.py::test_picklescan_padded_multi_stream_upload	multi_stream_padded	4.1 KiB	1	1.66ms	1.66ms	-0.3%	stable
nested-payload-review	tests/benchmarks/test_picklescan_benchmarks.py::test_picklescan_nested_payload_review[nested_hex]	nested_hex	130 B	1	479.2us	479.7us	+0.1%	stable

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. Breezy!

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[ianw-oai]

Reviewed; this looks acceptable.