Reproduce development evaluation after gold disclosure, Python3 standard library only.

python3 evaluate.py --gold eval-gold.public.json --candidate candidate/pages.jsonl --controls controls --source pdfgeo.py.snapshot --out rerun --arm pdfgeo-r20

Output directory must not already exist. Full original PDF is not bundled; its provenance and SHA are in gold. Controls are previously generated whole-document outputs, not visual truth. The public gold is an explicitly labelled path-only derivative; original private frozen gold SHA remains recorded. Metadata candidate counts require the separate adjudication described in the report. This script reproduces all literal checks, not semantic page correctness.
