Clarify review-fix validation scope and require publication approval

[Yuchao Yan (msyyc)]

Summary

• Apply the existing lintdiff targeted formatting/linting procedure to tests-only fixes as well as production-rule fixes; keep corpus requirements tied to production-rule changes and preserve promotion validation.
• Record planned command scope, required/supplemental status, exact commands, exit codes, and durable evidence. Failed commands remain blockers rather than being silently replaced by narrower passes.
• Split fixes into preparation and publication: the same persistent fix agent must return the proposed diff and evidence, then wait for parent approval bound to the head and content before staging, committing, or pushing. Apply this to backlog fixes and every counted round.

Evidence

During #5440, a tests-only Copilot finding led the fix agent to run package-wide lint, which exited 1, then continue to commit/push after focused lint passed. Follow-up inspection found 228 package lint warnings across 11 files, none changed by that PR. develop-lintdiff-rule already prescribes changed-file lint, but the loop skill explicitly linked that procedure only to production-source changes. The missing pre-publication handoff also meant the parent discovered the failure only after the push.

This PR clarifies the validation scope without weakening the failure stop condition and adds an explicit agent-to-agent publication gate. It does not require another human approval prompt.

Scope and validation

Skill-only change based on feature/lintdiff-migration-new; head is msyyc:feature/review-fix-validation-gate. No rule code, fixtures, dependency files, or #5440 commits are included.

• Formatted the changed Markdown with the existing Prettier command.
• Reviewed the complete diff, Markdown reference, backlog/round flow, and failure safeguards.
• git diff --check and staged diff checks passed.
• No builds, source tests, corpus runs, or CI waiting for this documentation-only change.