fix(rescue): keep host orchestration single-hop

[vitry]

Summary

• require the top-level user-facing Codex agent to invoke ZCode Rescue directly
• make ordinary subagents finish with their existing tools instead of nesting another Rescue child
• carry a verbatim non-Rescue disclosure through the parent into the user-facing final response
• lock guard ordering and source/marketplace Skill parity with contract tests

Scope

Prompt/Skill behavior only. Runtime ownership, result, cancel, and protocol validation are unchanged because the companion has no trusted agent-ancestry signal.

Verification

• uv run --with pyyaml python .../quick_validate.py skills/rescue
• npm run check
• node --test tests/skills-contracts.test.mjs (12/12)
• git diff --check origin/main...HEAD
• source/marketplace Rescue Skill byte comparison
• independent specification and quality reviews: Ready