Repair Experiment 013 Stage-A capture isolation

[Labeeb2339]

What changed

• add a NumPy-only frozen Stage-A artifact contract so capture authorization never imports Torch
• exact-load and source-bind that contract in the sealed runner, resolver, screen, and owned authorizer
• strengthen differential and real isolated-path tamper regressions
• retire the failed pre-repair evidence chain and require a fully fresh H0 chain

Local verification

• 2,093 passed, 28 skipped in the lockfile-exact clean environment (torch==2.13.0)
• ruff check .
• generated README asset/provenance check
• wheel and sdist build; strict Twine validation
• wheel contains recurquant/static_q468_artifact_contract.py

This remains a requalification repair. It does not claim a breakthrough or authorize reuse of the retired evidence chain.