Make the quality skill portable across Codex and Claude Code #47

Evidence

skills/crap-controlled-changes/SKILL.md requires superpowers:test-driven-development, which is not bundled or described as an installation prerequisite. It also assumes Claude's Bash timeout/background options and Read tool. Several command examples begin with ""/skills/..., which does not identify the installed package.

The CRAP, dead-code, mutation, and commit scripts already live together with language references and can remain shared.

Expected outcome

Either host can discover the quality skill, locate its installed helpers, and execute the same quality policy without relying on Claude-only tool instructions.

Acceptance criteria

• Preserve the existing metric thresholds, NEXT_ACTION handling, explicit acceptance rules, marker ownership, and language scope.
• Put host-specific tool invocation, long-running process handling, and output/exit-code collection in focused references; keep the quality policy in one shared location.
• Resolve bundled helpers relative to the installed skill/package, including cache paths and paths with spaces.
• Make the required TDD procedure self-contained or declare and verify a supported prerequisite on both hosts; a missing dependency must produce an actionable outcome.
• Remove unsupported timeout and background-process assumptions from the shared instructions. A yielded command is not a completed or successful gate.
• Validate skill discovery, helper execution, and a deliberately failing gate in clean environments on both hosts.
• Keep optional agent-eval integration optional; do not introduce model/API credentials for the measurement scripts.