XY-875 Align loop engineering docs and skills

[yvette-carlisle]

Summary

• Align loop guardrail docs with autonomous architecture recovery and Authority Boundary Check semantics.
• Update post-review/review orchestration specs so review churn stops the current strategy before bounded recovery or human-required routing.
• Sync Decodex plugin skills and manual CLI guidance with the new loop engineering behavior.

Validation

• cargo make fmt
• cargo make lint-fix
• cargo make test (1035 passed, 1 skipped)
• git diff --check

Recovery note

The retained XY-875 lane reached docs/skills patch + partial verification, then the app-server thread entered systemError/usageLimitExceeded before terminal handoff. I preserved the retained worktree, reviewed the diff, completed validation manually, and created this PR from the lane branch.

[yvette-carlisle]

Manual Decodex Review recovery evidence for XY-875 at head 6d532c0:\n\n- Fresh-context/read-only review findings R1/R2 were repaired.\n- Follow-up finding R3 on guardrail recovery skill wording was repaired and rechecked clean.\n- Local validation: cargo make fmt; cargo make test (1035 passed, 1 skipped); git diff --check.\n- GitHub checks: CodeQL / Analyze actions / JS-TS / Python / Rust green.\n\nDecodex status classifies the lane as ready_to_land for PR #295.