Fix real-host candidate minimal workflow

[AdvancingTitans]

Root cause

The first real Codex core gate correctly rejected candidate rollouts that ran extra rg/jq/wc/sed inspection commands outside the Task v2 allowlist. Safe shell unwrapping and scoring were working as designed.

Fix

• tighten only the release candidate guidance to execute the single prompt-provided trusted Trace command
• add a generated-candidate content contract test
• do not change the production Skill, scorer, or Task allowlist

Verification

• one-pair real Codex preflight: baseline FAIL (6 commands), candidate PASS (1 exact Trace command)
• 176 tests + 353 subtests passed
• business: 7 tests + 166 subtests passed
• strict audit: 0 FAIL / 0 UNKNOWN