Resolve six conflicts:
- hooks/hooks.metadata.json: keep this branch's gateguard description and
fingerprint, add upstream's hookify-runtime entries.
- package.json: keep both gateguard-report.js and github-coordination.js.
- scripts/hooks/gateguard-fact-force.js, tests/hooks/gateguard-fact-force.test.js,
skills/gateguard/SKILL.md: upstream added a simpler session denial cap; this
branch already has the fuller one (cap threaded through
markCheckedAndCountDenial, malformed-value warning, miss and target notes),
so keep it. Upstream's taskset and su wrapper handling, fail-closed
recursion limit and soft-hyphen sanitising merged cleanly and their tests pass.
- manifests/context-packs/skill-triggers@1.json: take upstream's file and
recompute registryDigest for the merged registry.
Add a repo-level supply-chain incident response playbook for npm/GitHub Actions package-registry incidents, anchored on the May 2026 TanStack compromise and prior Shai-Hulud-style npm incidents.
- add `docs/security/supply-chain-incident-response.md` with exposure checks, immediate response steps, workflow rules, publication rules, and escalation triggers
- link the playbook from `SECURITY.md`
- reject `pull_request_target` workflows that restore or save shared dependency caches
- add a regression test for the new `pull_request_target + actions/cache` guardrail
Validation:
- node tests/ci/validate-workflow-security.test.js (12 passed, 0 failed)
- node scripts/ci/validate-workflow-security.js (validated 7 workflow files)
- npx markdownlint-cli 'SECURITY.md' 'docs/security/supply-chain-incident-response.md'
- npx markdownlint-cli '**/*.md' --ignore node_modules
- git diff --check
- node tests/run-all.js (2377 passed, 0 failed)
- GitHub CI for #1848 green across Ubuntu, Windows, and macOS
No release, tag, npm publish, plugin tag, marketplace submission, or announcement was performed.
montjeffrey