feat(skills): add optional independent engineering review

[Phelan164]

Summary

Engineering-loop mentions independent review but does not define the review context, the code revision covered, or how to evaluate findings. Add an optional procedure for a fresh reviewer session, including one using the same model, with read-only candidate access, evidence-backed findings, disposition, and review of later changes.

Extend the measured task receipt with per-attempt reviewer evidence and usage accounting. Credit Code Mower's architecture and calibration policy as inspiration. Record this personal repository's explicit exemption from Jira ticket requirements in AGENTS.md.

Validation

• python3 scripts/validate_repo.py
• Playground tests pass when the lab changed — not applicable; labs unchanged
• Changed skills pass quick_validate.py
• Version-sensitive product claims link to official documentation — no new product capability claims; source inspiration uses pinned repository links

Wiki lint passed with 6 pages and no warnings; git diff --check passed. Skill validation used an isolated uv runtime with PyYAML. Checks establish document and skill validity; no independent-review efficiency experiment was run.

Safety and scope

• Examples contain no credentials or destructive defaults
• Community practices are labeled as such
• The change is limited to the described scope

Independent review remains conditional on task need and authorized host capabilities. The procedure does not grant merge authority, promise model diversity from a fresh session, or implement runtime enforcement. Existing local installations are not automatically changed by this PR. Revert this commit to restore the previous workflow.