pr-retrospectivelisted

# PR Retrospective ## Project wiring (the parent library's instantiation; adopters substitute their own) Portable procedure, concrete names. In the parent GRC library this skill runs with: - Improvement-log register: the improvement-log register in the consuming project's working state (the append-only per-PR retrospective register this skill writes; one row per merged PR). - Worker-hallucination metrics register: the worker-hallucination-metrics ledger in the consuming project's working state (the apply-time worker-correction log consumed as retrospective input). - Worker-brief template: the worker-brief template in the consuming project's working state (the worker-side guard-rail carrier that pattern findings may extend). - Sibling per-PR validation-sweep history register: the register in the consuming project's working state (whose reverse-chronological row convention the improvement-log register mirrors). - The parent register's concrete table header keeps its original columns (`Date | PR | FR closed | ...`); the generic output format below names that column `Backlog item closed`, and the parent's paired slash-command stub carries the concrete form. An adopting project maps each bullet to its own records; the procedure below refers to them generically. ## Overview After the PR-scoped validation sweep and before merge, conduct a brief retrospective on the PR's process. (Command names `/retro`, `/validate-pr`, and `/validate` are the parent library's paired commands,