docs: introduce CI security + supply-chain stack (ADR-023 + PRD)

- ADR-023 codifies the four-pillar enforcement stack: Renovate for
  bumps + Action SHA pinning via pinGitHubActionDigests, Socket.dev
  as a 9th hard filter in evaluate-library (free App + self-hosted
  socket-cli + reviewer-prompt enforcement), weekly trace
  revalidation cron with two-tier divergence action (rolling
  dashboard issue + per-dep re-evaluation issues), and the baseline
  GitHub-native gates (CodeQL, pnpm audit signatures, gitleaks
  pre-commit + native push protection). Failure-mode hierarchy is
  the single source of truth referenced by the sandcastle reviewer.
- Section 6 amends ADR-022 in place: major-bump re-evaluation
  trigger (minor/patch bumps skip), last-revalidated frontmatter
  field (preserves original date for adoption provenance), and
  Socket as the 9th hard filter. ADR-022 stays unedited; both ADRs
  read as a composed policy.
- PRD at docs/work/prds/2026-05-14-ci-security-and-supply-chain.prd.md
  seeds the implementation epic; explicit sequencing -- depends on
  the in-flight library-evaluation epic's stories 01/02/04/06
  landing first.
- Glossary gains "Trace revalidation" + "Major-bump re-evaluation"
  entries referenced by both ADRs.

Catalyst: 2026-05-14 audit confirmed zero security tooling in the
repo + GitHub Actions pinned to major-version tags (the tj-actions/
changed-files attack class). ADR-022 closes the adoption-time gate;
ADR-023 closes the post-adoption drift gate.

docs/work/_state.json

@@ -1,5 +1,5 @@
 {
-  "updated_at": "2026-05-14T10:14:22.260Z",
+  "updated_at": "2026-05-14T16:47:27.076Z",
   "epics": {
     "2026-05-13-binder-wrap-helper": {
       "status": "done",