Finalize Step: lessons-housekeeping

Purpose

Perform lessons-learned housekeeping after a plan finishes. Reason from the just-completed plan's outcome (what it changed, what it codified, which failure modes it eliminated) about the standing lessons-learned corpus, reconciling it into an actionable-by-construction queue rather than running a plain remove/trim pass:

• Remove lessons the plan made wholly redundant — the guarded failure mode can no longer occur, or the recommended practice is now codified/enforced, and no durable reusable rule remains to relocate.
• Promote-then-retire lessons that are completely covered and whose residue is a durable reusable rule — promote that rule into the governing skill's standards//references/ (or CLAUDE.md for repo-wide rules), cross-referencing the originating lesson id, then tombstone + remove the now-promoted lesson.
• Trim lessons the plan made only partly redundant, removing the now-covered portion while preserving the still-relevant guidance.
• Retain everything else, biasing toward retention whenever coverage is ambiguous.

Every change — removal, promotion-then-retire, adaptation, or deliberate retain — is recorded to the decision log so the housekeeping is fully auditable.

Interface Contract

Invoked by plan-marshall:phase-6-finalize for projects that include project:finalize-step-lessons-housekeeping in their phase-6-finalize.steps list.

Accepts the standard finalize-step arguments: