chore(agent): retain review finding patterns

[sanohiro]

Summary

• add a tracked, auditable ledger of recent independent review findings grouped by root-cause class
• count distinct finding events and affected PRs separately, with promotion thresholds for checklist and automated-owner coverage
• feed the three recurring classes back into align-self-review: complete validation phases, SQL scanner sibling states, and native link-order closure
• refresh the live pkg.db handoff and record the user-directed formal release checkpoint after D14

Verification

• git diff --check
• ledger count consistency check for the three promoted root-cause classes
• scripts/pre-pr.sh --docs-only